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Sample records for ataxia-telangiectasia cells exposed

  1. Chromosome aberrations in ataxia telangiectasia cells exposed to heavy ions

    Science.gov (United States)

    Kawata, T.; Cucinotta, F.; George, K.; Wu, H.; Shigematsu, N.; Furusawa, Y.; Uno, T.; Isobe, K.; Ito, H.

    Understanding of biological effects of heavy ions is important to assess healt h risk in space. One of the most important issues may be to take into account individual susceptibility. Ataxia telangiectasia (A-T) cells are known to exhibit abnormal responses to radiations but the mechanism of hyper radiosensitivity of A-T still remains unknown. We report chromosome aberrations in normal human fibroblasts and AT fibroblasts exposed to low- and high-LET radiations. A chemical-induced premature chromosome condensation (PCC) technique combined with chromosome- painting technique was applied to score chromosome aberrations in G2/M-phase cells. Following gamma irradiation, GM02052 cells were approximately 5 times more sensitive to g-rays than AG1522 cells. GM02052 cells had a much higher frequency of deletions and misrejoining than AG1522 cells. When the frequency of complex type aberrations was compared, GM02052 cells showed more than 10 times higher frequency than AG1522 cells. The results will be compared with those obtained from high-LET irradiations.

  2. Ionizing radiation and cell cycle progression in ataxia telangiectasia

    International Nuclear Information System (INIS)

    Exposure of mammalian cells to ionizing radiation causes delay in normal progress through the cell cycle at a number of different checkpoints. Abnormalities in these checkpoints have been described for ataxia telangiectasia cells after irradiation. In this report we show that these abnormalities occur at different phases in the cell cycle in several ataxia telangiectasia lymphoblastoid cells. Ataxia telangiectasia cells, synchronized in late G1 phase with either mimosine or aphidicolin and exposed to radiation, showed a reduced delay in entering S phase compared to irradiated control cells. Failure to exhibit G1-phase delay in ataxia telangiectasia cells is accompanied by a reduced ability of radiation to activate the product of the tumor suppressor gene p53, a protein involved in G1/S-phase delay. When the progress of irradiated G1-phase cells was followed into the subsequent G2 and G1 phases ataxia telangiectasia cells showed a more pronounced accumulation in G2 phase than control cells. When cells were irradiated in S phase and extent of delay was more evident in G2 phase and ataxia telangiectasia cells were delayed to a greater extent. These results suggest that the lack of initial delay in both G1 and S phases to the radiosensitivity observed in this syndrome. 26 refs., 3 figs., 2 tabs

  3. Chromosome Aberrations in Normal and Ataxia-Telangiectasia Cells Exposed to Heavy Ions

    Science.gov (United States)

    Kawata, T.; Ito, H.; Liu, C.; Shigematsu, N.; George, K.; Cucinotta, F. A.

    2007-01-01

    Although cells derived from Ataxia Telangiectasia (AT) patients are known to exhibit abnormal responses to ionizing radiations, its underlying mechanism still remains unclear. Previously, the authors reported that at the same gamma-irradiation dose AT cells show higher frequencies of misrepair and deletions compared to normal human fibroblast cells. In this study, we investigated the effects of heavy ions beams on chromosomal aberrations in normal and AT cells. Normal and AT fibroblast cells arrested at G0/G1 phase were irradiated with 2 Gy of X-rays, 490 MeV/u Silicon (LET 55 keV/m), 500 MeV/u Iron (LET 185 keV/m) and 200 MeV/u Iron (LET 440 keV/m) particles, and then cells were allowed to repair for 24 hours at 37 degrees before subculture. Calyculin-A induced PCC method was employed to collect G2/M chromosomes and whole DNA probes 1 and 3 were used to analyze chromosomal aberrations such as color-junctions, deletions, simple exchanges (incomplete and reciprocal exanges) and complex-type exchanges. The percentages of aberrant cells were higher when normal and AT cells were exposed to heavy ions compared to X-rays, and had a tendency to increase with increasing LET up to 185 keV/m and then decreased at 440 keV/m. When the frequency of color-junctions per cell was compared after X-ray exposure, AT cells had around three times higher frequency of color-junctions (mis-rejoining) than normal cells. However, at 185 keV/m there was no difference in the frequency of color-junctions between two cell lines. It was also found that the frequency of simple exchanges per cell was almost constant in AT cells regardless LET levels, but it was LET dependent for normal cells. Interestingly, the frequency of simple exchanges was higher for AT cells when it was compared at 185 keV/m but AT cells had more complex-type exchanges at the same LET levels. Heavy ions are more efficient in inducing chromosome aberrations in normal and AT cells compared to X-rays, and the aberration types

  4. Host cell reactivation of sunlamp-exposed adenovirus in fibroblasts from patients with Bloom's syndrome, ataxia telangiectasia, and Huntington's disease

    International Nuclear Information System (INIS)

    In this study, a sensitive host cell reactivation (HCR) technique was used to examine the repair capacity for DNA damaged by sunlamp exposure in fibroblast strains derived from 5 normal individuals and 8 patients representing three different diseases associated with DNA repair deficiencies. Adenovirus type 2 (Ad 2) was exposed to radiation from a GE 275 W sunlamp and subsequently used to infect fibroblast monolayers. At 48 hr after infection, cells were scored for the presence of viral structural antigens (Vag) using indirect immunofluorescent staining. Previous reports using this technique showed a substantial reduction in the HCR of sunlamp-exposed Ad 2 for infection of excision repair deficient fibroblasts from patients with xeroderma pigmentosum. In contrast, the HCR of Vag synthesis for sunlamp-exposed Ad 2 was in the normal range for the three ataxia telangiectasia, three Bloom's syndrome, and two Huntington's disease fibroblasts strains

  5. Cell biological study on ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Diagnosis of ataxia-telangiectasia (AT) has largely been dependent on the clinical findings such as cerebellar ataxia, telangiectasia, and immunological deficiency. However, diagnosis of AT by these ordinary criteria is sometimes not sufficient because of the lack of immunological abnormalities. We examined three cases of AT by ordinary clinical criteria and also by X-ray sensitivity of cultured skin fibroblasts. Case 1, a 9-year-old boy, revealed typical clinical features of AT. However, he had no abnormality in serum IgA or IgE. Case 2, a 10-year-old boy, showed decreased serum IgA level. Case 3, a 19-year-old female, had typical clinical features of AT with normal serum IgA, and developed papillary adenocarcinoma of thyroid which was surgically removed. Fibroblast strains derived from these three cases of AT and from the parents of Case 3 were examined with regard to X-ray sensitivity. Three fibroblast strains derived from AT patients (AT homozygotes) showed remarkable hypersensitivity to X-ray. Fibroblast strains derived from the parents (AT heterozygotes) of Case 3, however, showed normal X-ray sensitivity. Recently, AT fibroblasts have been known to show hypersensitivity also to some mutagen like neocarzinostazin as reported by Shiloh et al. Fibroblasts from Case 3 revealed hypersensitivity to neocarzinostazin. However, the sensitivity of the strains from AT heterozygotes (the parents of Case 3) showed no apparent difference from that of control cells. The assay system for mutagen is quite unstable and proper conditioning of the seeding cell number is important for the carrier detection. However, the diagnosis of AT homozygotes was definitely established by X-ray irradiation to cultured fibroblasts from patients. (author)

  6. Kinetics of chromatid aberrations in G2 ataxia-telangiectasia cells exposed to X-rays and ara A

    International Nuclear Information System (INIS)

    The cytogenetic effects of X-rays alone or in combination with 9-β-D-arabinofuranosyladenine (ara A) were studied in an immortalized fibroblastic line of ataxia-telangiectasia (A-T) cells. It is postulated that the kinetics of disappearance (rejoining) of chromatid deletions with postirradiation incubation time reflects the underlying repair of dsb, and is inhibited by ara A. The rejoining kinetics for deletions in A-T was similar to that found in a previous study of normal human fibroblasts (Mozdarani and Bryant 1987). The number of deletions in X-irradiated A-T cells at 1.5 h before fixation was found to be higher by a factor of approximately 2 than that found previously in normals, indicating that in A-T a higher rate of conversion of dsb into chromatid deletions occurs. The frequency of exchanges induced in G2 A-T cells was similarly enhanced but, unlike the situation in normal cells, ara A was found to cause only a slight increase in this frequency. (author)

  7. Ataxia - telangiectasia

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/001394.htm Ataxia - telangiectasia To use the sharing features on this page, please enable JavaScript. Ataxia-telangiectasia is a rare childhood disease. It affects ...

  8. DNA strand breakage repair in ataxia telangiectasia fibroblast-like cells

    International Nuclear Information System (INIS)

    Human diploid fibroblast-like cells derived from four patients with the genetic disease ataxia telangiectasia and from two non-mutant donors were examined for the repair of X-ray induced strand breaks in DNA. The ataxia telangiectasia cultures showed no significant differences from the non-mutant cultures in the kinetics and extent of strand repair. This suggests that the increased spontaneous and X-ray induced chromatid aberrations observed in ataxia telangiectasia cells are not caused by a defect in the repair of single strand breaks as might be suspected from a general model of aberration production

  9. The effect of bleomycin on DNA synthesis in ataxia telangiectasia lymphoid cells

    International Nuclear Information System (INIS)

    Bleomycin, a radiomimetic glycopeptide, inhibits de novo DNA synthesis in ataxia telangiectasia lymphoblastoid B cells to a markedly lesser extent than in normal and xeroderma pigmentosum lymphoid cells. This observation is similar to that following ionizing radiation; however, the effect is slower following the chemical treatment. Recovery of the normal cells occurs 15-18 hours after treatment, whereas the ataxia telangiectasia lines do not attain normal levels of DNA synthesis during the entire 24-hour observation period. Similar differences were not observed following treatment with mitomycin C, a bifunctional alkylating agent, indicating a specific effect of bleomycin on DNA synthesis in ataxia telangiectasia cells. Following bleomycin treatment and preincubation with hydroxyurea, residual DNA synthesis in ataxia telangiectasia cells was similar to that in both normal and xeroderma pigmentosum lymphoid lines, suggesting that the capacity to repair the induced DNA lesion is present

  10. Ataxia Telangiectasia

    Science.gov (United States)

    Ataxia-telangiectasia (A-T) is a rare, inherited disease. It affects the nervous system, immune system, and ... young children, usually before age 5. They include Ataxia - trouble coordinating movements Poor balance Slurred speech Tiny, ...

  11. Nature of a defect in cells from individuals with ataxia-telangiectasia

    International Nuclear Information System (INIS)

    The cells and tissues of patients with ataxia-telangiectasia (A-T), an inherited disease characterized by a high degree of proneness to cancer, are abnormally sensitive to ionizing radiation. Noncycling cultures of normal human and A-T fibroblasts were exposed to x-rays so that the breakage and rejoining of prematurely condensed chromosomes in the G1 phase could be compared. After a dose of 6.0 grays, both cell types had the same initial frequency of breaks and the same rate for rejoining of the breaks, but the fraction of breaks that did not rejoin was five to six times greater for the A-T cells. The results also show that progression of cells into the S phase is not a prerequisite for the increased frequency of chromosome fragments that appear in mitosis after A-T cells are irradiated in the G1 or G0 phase

  12. The response of ataxia-telangiectasia lymphoblastoid cells to neutron irradiation

    International Nuclear Information System (INIS)

    The response of control and ataxia-telangiectasia (A-T) cells to increasing doses of high-linear-energy-transfer (LET) ionizing radiation (neutrons) was compared. Ataxia-telangiectasia cells were markedly more sensitive to neutron irradiation than were control cells. The D0 value for the two A-T cell lines was 0.4 Gy while the value for controls was approximately 1.4 Gy. Fast neutrons were considerably more effective than gamma rays in inducing cell death in both cell types, but the sensitivity factor remained approximately the same as with gamma rays. A minimal depression of DNA synthesis was observed in ataxia-telangiectasia cells after neutron irradiation, similar to that reported previously after gamma irradiation. The extent of inhibition was not significantly greater in control cells, contrary to that seen with gamma rays. In time-course experiments a significant difference in degree of inhibition of DNA synthesis was observed between the cell types. Low doses of fast neutrons induced a G2-phase delay in both cell types, but the degree and extent of this delay was greater in ataxia-telangiectasia cells as observed previously with low-LET radiation

  13. Ionizing radiation and DNA-chain elongation in ataxia telangiectasia lymphoblastoid cells

    International Nuclear Information System (INIS)

    DNA-chain elongation rates, determined by sedimentation analysis, were found to be similar in control and ataxia-telangiectasia lymphoblastoid cells. A γ-radiation dose of 6 Gray, which had previously been shown to have a marked inhibitory effect on initiation of DNA-replication, had no appreciable effect on elongation rates in either cell type. Elongation rates were also determined at 20 Gray of γ-rays by pulsing cells with [3H]thymidine prior to irradiation to avoid anomalous sedimentation behaviour. At this radiation dose elongation was almost completely inhibited in control cells while little or no inhibition was observed in ataxia-telangiectasia cells. Deoxyribonucleoside triphosphate pool equilibration times were not altered at either dose. (Auth.)

  14. Endonucleolytic activity for γ-irradiated DNA in normal and ataxia telangiectasia fibroblast cell extracts

    International Nuclear Information System (INIS)

    The increased sensitivity of ataxia telangiectasia cells towards ionizing radiation may be related to their inability to incise DNA near sites of radiation-induced base damages. When compared to 3 unaffected controls, crude extracts from 5 lines of fibroblast cells derived from ataxia telangiectasia patients were capable of incising γ-irradiated DNA to the same extent as normal cells as determined in a nicking assay, using the circular replicative form of PHI X 174. However, the types of alterations introduced into DNA by γ-irradiation could be distinguished from sites of base loss due to depurination or depyrimidination and from sites of base modification by OsO4. The specific endonuclease by its rate of temperature inactivation. (orig.)

  15. Effect of hypertonicity and X radiation on DNA synthesis in normal and ataxia-telangiectasia cells

    International Nuclear Information System (INIS)

    Normal human cells and cells from patients with ataxia-telangiectasia (A-T) were exposed to culture medium made hypertonic by raising the NaCl concentration. The rate of DNA synthesis in both types of cells was depressed as a function of increasing hypertonicity. When cells of both types were exposed to X radiation and incubated in hypertonic medium, DNA synthesis appeared to be more radioresistant than in cells incubated in normal medium. Velocity sedimentation analysis showed that this was due to a hypertonicity-induced inhibition of replicon initiation, which is the same process affected by X radiation, indicating that the two treatments were not additive. After a 5-hr incubation in hypertonic medium, there was a new steady state of replicon initiation and elongation similar to that existing in cells grown in normal medium, except that fewer replicons were participating. At this time DNA synthesis in each type of cell had a characteristic response to radiation, i.e., radiosenstivie in normal cells and radioresistant in A-T cells. These results suggest that radioresistant DNA synthesis in A-T cells is not due to increased condensation of chromatin

  16. Targeted disruption of Ataxia-telangiectasia mutated gene in miniature pigs by somatic cell nuclear transfer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young June; Ahn, Kwang Sung; Kim, Minjeong; Kim, Min Ju; Park, Sang-Min; Ryu, Junghyun; Ahn, Jin Seop; Heo, Soon Young; Kang, Jee Hyun; Choi, You Jung [Department of Nanobiomedical Science and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan (Korea, Republic of); Choi, Seong-Jun [Institute of Tissue Regeneration Engineering, Dankook University, Cheonan (Korea, Republic of); Shim, Hosup, E-mail: shim@dku.edu [Department of Nanobiomedical Science and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan (Korea, Republic of); Institute of Tissue Regeneration Engineering, Dankook University, Cheonan (Korea, Republic of); Department of Physiology, Dankook University School of Medicine, Cheonan (Korea, Republic of)

    2014-10-03

    Highlights: • ATM gene-targeted pigs were produced by somatic cell nuclear transfer. • A novel large animal model for ataxia telangiectasia was developed. • The new model may provide an alternative to the mouse model. - Abstract: Ataxia telangiectasia (A-T) is a recessive autosomal disorder associated with pleiotropic phenotypes, including progressive cerebellar degeneration, gonad atrophy, and growth retardation. Even though A-T is known to be caused by the mutations in the Ataxia telangiectasia mutated (ATM) gene, the correlation between abnormal cellular physiology caused by ATM mutations and the multiple symptoms of A-T disease has not been clearly determined. None of the existing ATM mouse models properly reflects the extent to which neurological degeneration occurs in human. In an attempt to provide a large animal model for A-T, we produced gene-targeted pigs with mutations in the ATM gene by somatic cell nuclear transfer. The disrupted allele in the ATM gene of cloned piglets was confirmed via PCR and Southern blot analysis. The ATM gene-targeted pigs generated in the present study may provide an alternative to the current mouse model for the study of mechanisms underlying A-T disorder and for the development of new therapies.

  17. Targeted disruption of Ataxia-telangiectasia mutated gene in miniature pigs by somatic cell nuclear transfer

    International Nuclear Information System (INIS)

    Highlights: • ATM gene-targeted pigs were produced by somatic cell nuclear transfer. • A novel large animal model for ataxia telangiectasia was developed. • The new model may provide an alternative to the mouse model. - Abstract: Ataxia telangiectasia (A-T) is a recessive autosomal disorder associated with pleiotropic phenotypes, including progressive cerebellar degeneration, gonad atrophy, and growth retardation. Even though A-T is known to be caused by the mutations in the Ataxia telangiectasia mutated (ATM) gene, the correlation between abnormal cellular physiology caused by ATM mutations and the multiple symptoms of A-T disease has not been clearly determined. None of the existing ATM mouse models properly reflects the extent to which neurological degeneration occurs in human. In an attempt to provide a large animal model for A-T, we produced gene-targeted pigs with mutations in the ATM gene by somatic cell nuclear transfer. The disrupted allele in the ATM gene of cloned piglets was confirmed via PCR and Southern blot analysis. The ATM gene-targeted pigs generated in the present study may provide an alternative to the current mouse model for the study of mechanisms underlying A-T disorder and for the development of new therapies

  18. Analysis of Residual DSBs in Ataxia-Telangiectasia Lymphoblast Cells Initiating Apoptosis

    Directory of Open Access Journals (Sweden)

    Teresa Anglada

    2016-01-01

    Full Text Available In order to examine the relationship between accumulation of residual DNA double-strand breaks (DSBs and cell death, we have used a control and an ATM (Ataxia-Telangiectasia Mutated defective cell line, as Ataxia-Telangiectasia (AT cells tend to accumulate residual DSBs at long times after damage infliction. After irradiation, AT cells showed checkpoint impairment and a fraction of cells displayed an abnormal centrosome number and tetraploid DNA content, and this fraction increased along with apoptosis rates. At all times analyzed, AT cells displayed a significantly higher rate of radiation-induced apoptosis than normal cells. Besides apoptosis, 70–85% of the AT viable cells (TUNEL-negative carried ≥10 γH2AX foci/cell, while only 12–27% of normal cells did. The fraction of AT and normal cells undergoing early and late apoptosis were isolated by flow cytometry and residual DSBs were concretely scored in these populations. Half of the γH2AX-positive AT cells undergoing early apoptosis carried ≥10 γH2AX foci/cell and this fraction increased to 75% in late apoptosis. The results suggest that retention of DNA damage-induced γH2AX foci is an indicative of lethal DNA damage, as cells undergoing apoptosis are those accumulating more DSBs. Scoring of residual γH2AX foci might function as a predictive tool to assess radiation-induced apoptosis.

  19. Stable radioresistance in ataxia-telangiectasia cells containing DNA from normal human cells

    International Nuclear Information System (INIS)

    SV40-transformed ataxia-telangiectasia (AT) cells were transfected with a cosmid containing a normal human DNA library and selectable marker, the neo gene, which endows successfully transformed mammalian cells with resistance to the antibiotic G418. Cells from this line were irradiated with 50 Gy of X-rays and fused with non-transfected AT cells. Among the G418-resistant colonies recovered was one stably resistant to radiation. Resistance to ionizing radiation of both primary transfectant line and its fusion derivative was intermediate between that of AT cells and normal cells, as assayed by colony-forming ability and measurement of radiation-induced G2 chromatic aberrations; both cell lines retained AT-like radioresistant DNA synthesis. Results suggest that, because radioresistance in transfected cells was not as great as in normal human cells, two hallmarks of AT, radiosensitivity and radioresistant DNA synthesis, may still be the result of a single defective AT gene. (author)

  20. Cell and Molecular Biology of Ataxia Telangiectasia Heterozygous Human Mammary Epithelial Cells Irradiated in Culture

    Science.gov (United States)

    Richmond, Robert C.

    2001-01-01

    Autologous isolates of cell types from obligate heterozygotes with the autosomal disorder ataxia-telangiectasia (A-T)were used to begin a tissue culture model for assessing pathways of radiation-induced cancer formation in this target tissue. This was done by establishing cultures of stromal fibroblasts and long-term growth human mammary epithelial cells (HMEC) in standard 2-dimensional tissue culture in order to establish expression of markers detailing early steps of carcinogenesis. The presumptive breast cancer susceptibility of A-T heterozygotes as a sequel to damage caused by ionizing radiation provided reason to study expression of markers in irradiated HMEC. Findings from our study with HMEC have included determination of differences in specific protein expression amongst growth phase (e.g., log vs stationary) and growth progression (e.g., pass 7 vs pass 9), as well as differences in morphologic markers within populations of irradiated HMEC (e.g., development of multinucleated cells).

  1. DNA-mediated gene transfer into ataxia-telangiectasia cells

    International Nuclear Information System (INIS)

    The complete description of the genetic lesion(s) underlying the AT mutation might, therefore, highlight not only a DNA-repair pathwa, but also an important aspect of the physiology of lymphocytes. DNA-mediated gene transfer into eukaryotic cells has proved a powerful tool for the molecular cloning of certain mammalian genes. The possibility to clone a given gene using this technology depends, basically, on the availability of a selectable marker associated with the expression of the transfected gene in the recipient cell. Recently, a human DNA repair gene has been cloned in CHO mutant cells by taking advantage of the increased resistance to ultraviolet radiation of the transformants. As a preliminary step toward the molecular cloning of the AT gene(s), the authors have attempted to confer radioresistance to AT cells by transfection with normal human DNA

  2. Rapid repair of potentially lethal damage in normal and ataxia telangiectasia cell lines

    International Nuclear Information System (INIS)

    Potentially lethal damage repair (PLDR) was investigated in two normal and three ataxia telangiectasia (AT) human-skin fibroblast cell lines cultured in vitro. Using plateau-phase cells, time kinetics and repair were measured after irradiation. PLDR depended on both dose and survival level, as previously seen in rodent cells. Human cells differed from rodent cells in PLDR speed and ability to discern two components within the repair response. Fast repair had a t1/2 of approximately 5-7 min; the slow response occurred over hours. AT cells had demonstrable PLDR contrasting previous studies. Quantitatively, the proportion of fast and slow repair was similar for each dose in either normal or AT cells. However, AT cells had lower levels of both types of repair. When analyzing PLDR in human cells, differences in repair rates between human and rodent cells must be considered. (author)

  3. [From gene to disease; ataxia telangiectasia

    NARCIS (Netherlands)

    Broeks, A.; Veer, L.J. van 't; Ottenheim, C.; Hiel, J.A.P.; Kleijer, W.J.; Weemaes, C.M.R.

    2003-01-01

    Ataxia telangiectasia (AT) is an autosomal recessive disorder characterised by cerebellar ataxia, telangiectasia, immune defects, and a predisposition to malignancy. Chromosomal breakage is a feature. AT cells are abnormally sensitive to cell kill by ionising radiation and abnormally resistant to in

  4. Thermal enhancement of radiosensitivity in normal and ataxia telangiectasia human cells

    International Nuclear Information System (INIS)

    Normal human and ataxia telangiectasia (AT) fibroblasts were tested for enhancement of radiosensitivity by hyperthermia. In normal fibroblasts, thermal enhancement of radiosensitivity occurred at 42.00 and 45.00C and was greatest for simultaneous treatments of heat and radiation. This thermal enhancement decreased, as an incubation time at 37.00C was introduced either between heat and X-ray, or X-ray and heat, treatments. AT cells were more radiosensitive (D0=0.67 Gy) than normal cells (D0=1.4 Gy). Heating at 42.00 or 45.00C resulted in enhanced radiosensitivity, which was equal for heating before, during or after irradiation. These data show that normal human fibroblasts can recover from heat and radiation treatments, while AT fibroblasts lack this ability

  5. Ataxia-telangiectasia cell extracts confer radioresistant DNA synthesis on control cells

    International Nuclear Information System (INIS)

    We have investigated in greater detail the radioresistant DNA synthesis universally observed in cells from patients with ataxia-telangiectasia (A-T). The approach employed in this study was to permeabilize cells with lysolecithin after gamma-irradiation and thus facilitate the introduction of cell extract into these cells. This permeabilization can be reversed by diluting the cells in growth medium. Cells treated in this way show the characteristic inhibition (control cells) or lack of it (A-T cells) after exposure to ionizing radiation. Introduction of A-T cells extracts into control cells prevented the radiation-induced inhibition of DNA synthesis normally observed in these cells. A-T cell extracts did not change the level of radioresistant DNA synthesis in A-T cells. Control cell extracts on the other hand did not influence the pattern of inhibition of DNA synthesis in either cell type. It seems likely that the agent involved is a protein because of its heat lability and sensitivity to trypsin digestion. It has a molecular weight (MW) in the range 20-30 000 D. The development of this assay system for a factor conferring radioresistant DNA synthesis on control cells provides a means of purifying this factor, and ultimately an approach to identifying the gene responsible

  6. X-ray-induced G 2 arrest in ataxia telangiectasia lymphoblastoid cells

    International Nuclear Information System (INIS)

    Sensitivity to X-ray-induced G-2 arrest was compared between ataxia telangiectasia (AT) lymphoblastoid cells and normal human cells. Flow cytometrical analysis of cells following X-ray irradiation revealed that the fraction of cells with 4n DNA content was greater in AT cells than in normal cells as previously reported by other investigators. However, the other parameterss for cell-cycle progression kinetics including mitotic indices, cumulative mitotic indices and cumulative labelled mitotic indices indicated that X-ray-induced G-2 arrest as a function of dose in AT cells was indistinguishable from that in normal cells. Moreover, no significant difference in cell viability was noted between AT and normal cells until 48 h following X-irradiation up to 2.6 Gy, although X-irradiated At cells, compared to normal cells, showed a significantly decrease survival in terms of cell multiplication in growth medium and colony formation in soft agar. These data collectively suggest that the greater accumulation of AT cells with 4n DNA content in flow cytometry cannot be attributed to more stringent irreversible blockage of cell-cycle progression at the G-2 phase and eventual cell death there. The possible reasons for this greater accumulation are discussed. (Author). 19 refs.; 5 figs.; 2 tabs

  7. Cell cycle dependence of mitotic delay in X-irradiated normal and ataxia-telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    An investigation has been made of the relationship between suppression in the mitotic index and inhibition of DNA synthesis in normal (N) and ataxia-telangiectasia (A-T) skin fibroblasts, using tritiated thymidine as a marker of the cell cycle. The delay in progression of X-irradiated cells through the cell cycle, which is more pronounced in normal than in A-T fibroblasts, was greatest for cells in G2 at the time of irradiation. The greater effect of radiation on the initiation of DNA synthesis in N than in A-T cells was reflected in the shape of the percent labelled mitosis curves after 3H-thymidine treatment. The duration of the S phase in unirradiated A-T cells was greater than in N cells. It is pointed out that any explanation of the underlying defect in A-T must account not only for the reduced radiosensitivity of DNA synthesis but for the lesser delay in G2. The authors claim that their data support the hypothesis that DNA is the principal target for radiation-induced G2 delay. (U.K.)

  8. Deficient repair of potentially lethal damage in actively growing ataxia telangiectasia cells

    International Nuclear Information System (INIS)

    The repair of potentially lethal damage after X rays was studied in exponentially growing normal and ataxia telangiectasia (A-T) strains of human fibroblasts. X-ray killing of all normal strains from six healthy persons was enhanced when cells were treated with hypertonic phosphate-buffered saline immediately after irradiation. This treatment is not toxic to unirradiated cells and demonstrates that ordinarily these cells repair potentially lethal damage. The potentially lethal damage in normal cells is repaired within 1 hr. In contrast, all A-T strains from four A-T patients were completely deficient in their ability to repair potentially lethal damage. Treatment with a hypertonic solution after X irradiation is known to increase the frequency of chromosomal aberrations and to enhance cell killing, as though hypertonicity had induced the A-T state in normal cells. These results support the inference that the increased radiosensitivity of A-T cells can be attributed to some defect in the repair of DNA damage rather than abnormal DNA synthesis following irradiation

  9. Impaired recovery and mutagenic SOS-like responses in ataxia telangiectasia cells

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, G. (Universite Libre de Bruxelles (Belgium) Rijksuniversiteit Leiden (Netherlands)); Abrahams, P.J. (Rijksuniversiteit Leiden (Netherlands)); Chen, Y.Q. (Universite Libre de Bruxelles (Belgium)); Schouten, R. (Rijksuniversiteit Leiden (Netherlands)); Cornelis, J.J. (Universite Libre de Bruxelles (Belgium) Institut Pasteur, 75 - Paris (France)); Lowe, J.E. (Sussex Univ., Brighton (UK)); Eb, A.J. van der (Rijksuniversiteit Leiden (Netherlands)); Rommelaere, J. (Universite Libre de Bruxelles (Belgium) Institut Pasteur, 75 - Paris (France))

    1989-01-01

    Radiosensitive fibroblasts from patients with ataxia telangiectasia (AT) were studied for their proficiency in two putative eukaryotic SOS-like responses, namely the enhanced reactivation (ER) and enhanced mutagenesis of damaged viruses infecting pre-irradiated versus mock-treated cells. A previous report indicated that, unlike normal human cells, a line of AT fibroblasts (AT5BIVA) could not be induced to express ER of damaged parvovirus H-1, a single-stranded DNA virus, by UV- or X-irradiation. In the present study, AT5BIVA fibroblasts were also distinguished from normal cells by the inability of the former to achieve enhanced mutagenesis of damaged H-1 virus upon cell UV-irradiation. In contrast, dose-response and time-course experiments revealed normal levels of ER of Herpes simplex virus 1, a double-stranded DNA virus, in X- or UV-irradiated AT5BIVA cells. Taken together, these data point to a possible deficiency of AT cells in a conditioned mutagenic process that contributes to a greater extent to the recovery of damaged single-stranded than double-stranded DNA. Such a defect may concern the replication of damaged DNA or the generation of signals promoting the latter process and may be related to the lack of radiation-induced delay that is typical of AT cell DNA synthesis. (author).

  10. Repair of ionizing radiation DNA base damage in ataxia-telangiectasia cells

    International Nuclear Information System (INIS)

    Micrococcus luteus endonuclease sensitive sites were measured by alkaline elution in normal human and ataxia-telangiectasia (AT) fibroblasts after ionizing radiation. Due to the sensitivity of this assay, repair of base damage after 3 to 6 kilorads has been measured after oxic or hypoxic radiation. With 5.5 kilorads of oxic radiation, more than 50% of the base damage was removed after 1.5 h of repair incubation in all cells, including exr+ and exr- AT cells, and approximately 75% was removed by 4 h. After 3 or 4.5 kilorads of hypoxic X-irradiation, repair was equivalent in normal and exr- AT cells. This study included three exr- AT strains which have been reported to be deficient in the removal of gamma-ray base damage at higher doses. Since these strains repaired ionizing radiation base damage normally at lower doses, which are more relevant to survival, it is concluded that the X-ray hypersensitivity of AT cells is probably not related to the repair of base damage

  11. Fixation and repair of radiation damage in normal and ataxia-telangiectasia human cells

    International Nuclear Information System (INIS)

    Post-x-irradiation exposure to anisotonic treatment (.05 or 1.5 mol/l NaCl) of potentially lethal damage occurred in both normal and ataxia-telangiectasia human fibroblasts when treated in plateau or exponential growth phase. (author)

  12. Ataxia-telangiectasia mutated (ATM) deficiency decreases reprogramming efficiency and leads to genomic instability in iPS cells

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, Taisuke [Department of Cell Differentiation, The Sakaguchi Laboratory, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Nagamatsu, Go, E-mail: gonag@sc.itc.keio.ac.jp [Department of Cell Differentiation, The Sakaguchi Laboratory, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Kosaka, Takeo [Department of Urology, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Takubo, Keiyo [Department of Cell Differentiation, The Sakaguchi Laboratory, School of Medicine, Keio University, Tokyo 160-8582 (Japan); Hotta, Akitsu [Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan); Department of Reprogramming Science, Center for iPS Cell Research and Application (CiRA), Kyoto University, Kyoto (Japan); Ellis, James [Ontario Human iPS Cell Facility, Molecular Genetics, University of Toronto, Developmental and Stem Cell Biology, SickKids, Toronto, Canada MG1L7 (Canada); Suda, Toshio, E-mail: sudato@sc.itc.keio.ac.jp [Department of Cell Differentiation, The Sakaguchi Laboratory, School of Medicine, Keio University, Tokyo 160-8582 (Japan)

    2011-04-08

    Highlights: {yields} iPS cells were induced with a fluorescence monitoring system. {yields} ATM-deficient tail-tip fibroblasts exhibited quite a low reprogramming efficiency. {yields} iPS cells obtained from ATM-deficient cells had pluripotent cell characteristics. {yields} ATM-deficient iPS cells had abnormal chromosomes, which were accumulated in culture. -- Abstract: During cell division, one of the major features of somatic cell reprogramming by defined factors, cells are potentially exposed to DNA damage. Inactivation of the tumor suppressor gene p53 raised reprogramming efficiency but resulted in an increased number of abnormal chromosomes in established iPS cells. Ataxia-telangiectasia mutated (ATM), which is critical in the cellular response to DNA double-strand breaks, may also play an important role during reprogramming. To clarify the function of ATM in somatic cell reprogramming, we investigated reprogramming in ATM-deficient (ATM-KO) tail-tip fibroblasts (TTFs). Although reprogramming efficiency was greatly reduced in ATM-KO TTFs, ATM-KO iPS cells were successfully generated and showed the same proliferation activity as WT iPS cells. ATM-KO iPS cells had a gene expression profile similar to ES cells and WT iPS cells, and had the capacity to differentiate into all three germ layers. On the other hand, ATM-KO iPS cells accumulated abnormal genome structures upon continuous passages. Even with the abnormal karyotype, ATM-KO iPS cells retained pluripotent cell characteristics for at least 20 passages. These data indicate that ATM does participate in the reprogramming process, although its role is not essential.

  13. Inverted duplication of JH associated with chromosome 14 translocation and T-cell leukemia in ataxia-telangiectasia.

    OpenAIRE

    Johnson, J P; Gatti, R A; Sears, T S; White, R. L.

    1986-01-01

    A specific 14q32 breakpoint is observed in a homologous chromosome 14 translocation [t(14;14)q12q32] occurring in the T-cells of about 10% of patients with ataxia-telangiectasia (AT). To investigate whether the 14q32 breakpoint in AT occurs within the immunoglobulin gene cluster as is frequently detected in B-cell lymphoma, immunoglobulin clones were hybridized to Southern blots of DNA isolated from the T-cells of two AT patients with this chromosome 14 translocation. The 14q32 translocation ...

  14. Molecular analysis of a t(14;14) translocation in leukemic T-cells of an ataxia telangiectasia patient

    International Nuclear Information System (INIS)

    The authors have detected and cloned two rearrangements in the T-cell receptor α locus from a clone of somatic cell hybrids carrying a t(14;14)(q11;q32) chromosomal translocation derived from an ataxia telangiectasia patient with T-cell chronic lymphocytic leukemia. The T-cell clone carrying the t(14;14) chromosomal translocation was known to be present for > 10 years before the onset of overt leukemia. One molecular rearrangement of the T-cell receptor α locus corresponded to a functional variable-joining region (V-J) joining, whereas the other derived from the breakpoint of the t(14;14)(q11;q32) translocation. Chromosomal in situ hybridization of the probe derived from the t(14;14) breakpoint localized the breakpoint region to 14q32.1, apparently the same region that is involved in another ataxia telangiectasia characteristic chromosome translocation, t(7;14)(q35;q32). The 14q32.1 breakpoint is at least 10,000 kilobase pairs (kbp) centromeric to the immunoglobulin heavy chain locus. Sequence analysis of the breakpoint indicates the involvement of a Jα sequence during the translocation. Comigration of high-molecular weight DNA fragments involved with t(7;14) and t(14;14) translocations suggests the presence of a cluster of breakpoints in the 14q32.1 region, the site of a putative oncogene, TCL1

  15. A gamma-ray-resistant derivative of an ataxia telangiectasia cell line obtained following DNA-mediated gene transfer

    International Nuclear Information System (INIS)

    Genomic DNA from normal human or mouse cells was transfected together with the selectable market gpt into the simian virus 40-transformed ataxia telangiectasia fibroblast line, AT5BIVA. From a series of experiments involving over 400 000 clones selected for the gpt marker, one unambiguously radiation-resistant clone (clone 67) was recovered following selection with repeated cyles of gamma irradiation. The normal level of radiation resistance of clone 67 has been maintained for at least 11 months in the absence of further selection by radiation. The resistant clone contains one copy of the gpt gene. Its DNA synthesis following gamma-radiation is inhibited to an extent intermediate between that of ataxia telangiectasia and normal cells. Three out of four thioguanine-resistant derivatives of clone 67 have either lost or do not express the gpt sequence and show almost the same sensitivity to gamma irradiation as the original AT5BIVA line. This suggests that the radiation resistance of clone 67 may be linked to the gpt sequence and may have arisen as a consequence of the transfection, rather than as the result of an independent mutation to radiation resistance. (author)

  16. Radiation Dose-effects on Cell Cycle, Apoptosis, and Marker Expression of Ataxia Telangiectasia-Heterozygous Human Breast Epithelial Cells

    Science.gov (United States)

    Cruz, A.; Bors, K.; Jansen, H.; Richmond, R.

    2003-01-01

    Ataxia-telangiectasia (A-T) is a radiation-sensitive genetic condition. AT-heterozygous human mammary epithelial cells (HMEC) were irradiated using a Cs137 source in order to compare cell cycle, apoptosis, and marker expression responses across 3 radiation doses. No differences in cell cycle and apoptosis were found with any of the radiation doses used (30, 60, and 90 rads) compared with the unirradiated control (0 rad). At the same doses, however, differences were found in marker expression, such as keratin 18 (kl8), keratin 14 (k14), insulin-like growth factor I receptor (IGF-IR), and connexin 43 (cx43). This may indicate that radiation sensitivity in the heterozygous state may be initiated through signal transduction responses.

  17. Caffeine Suppresses Apoptosis of Bladder Cancer RT4 Cells in Response to Ionizing Radiation by Inhibiting Ataxia Telangiectasia Mutated-Chk2-p53 Axis

    Institute of Scientific and Technical Information of China (English)

    Zhe-Wei Zhang; Jing Xiao; Wei Luo; Bo-Han Wang; Ji-Min Chen

    2015-01-01

    Background:Caffeine suppresses ataxia telangiectasia and Rad3 related and ataxia telangiectasia mutated (ATM) activities;ATM is the major kinase for DNA damage detection.This study aimed to investigate the effects of caffeine on DNA damage responses in cells from the bladder cancer cell line RT4 those were exposed to ionizing radiation (IR).Methods:Immunofluorescent staining was performed to investigate changes in the proteins involved in DNA damage responses with or without caffeine.A mouse xenograft model was used to study the effects of caffeine on the DNA damage responses.Western blotting was used to investigate the effects of caffeine pretreatment on the ATM-Chk2-p53-Puma axis,while real-time polymerase chain reaction (RT-PCR) assessed changes in messenger RNA levels of p53 and downstream targets responding to IR.Finally,terminal deoxynucleotidyl transferase-dUTP nick end labeling assay.Western blotting and colony formation assay were used to measure the effects of caffeine on radiation-related apoptosis.All of the data were analyzed with a two-tailed Student's t-test.Results:Immunofluorescent staining showed that caffeine pretreatment profoundly suppressed the formation ofγH2AXand p53-binding protein 1 foci in RT4 cells in response to irradiation.Cellular and animal experiments suggested that this suppression was mediated by suppression of the ATM-Chk2-p53-Puma DNA damage-signaling axis.RT-PCR indicated caffeine also attenuated transactivation of p53 and p53-inducible genes.The colony formation assay revealed that caffeine displayed radioprotective effects on RT4 cells in response to low-dose radiation compared to the radiosensitization effects on T24 cells.Conclusion:Caffeine may inhibit IR-related apoptosis of bladder cancer RT4 cells by suppressing activation of the ATM-Chk2-p53-Puma axis.

  18. Effect of X-radiation on DNA and histone synthesis in ataxia telangiectasia and normal lymphoblastoid cells

    International Nuclear Information System (INIS)

    The possibility that the radiosensitivity of lymphoblastoid cell lines from patients with ataxia telangiectasia (A-T) is due to an aberrant content of histones has been examined. The histone pattern of lymphoblastoid cell lines derived from A-T patients was found to be indistinguishable from that obtained from normal individuals. X-ray irradiation led to a greater decrease in cell growth rate in the A-T cells than in the normal cells but was accompanied by a greater decrease of DNA synthesis rate in the normal cells. This difference in radiosensitivity was not reflected in differences in the content or rates of synthesis of histones or of major non-histone proteins in these cells. The authors conclude that the hypersensitivity to ionizing radiation in A-T cells is not due to fundamental differences in the composition or synthesis of the major chromosomal proteins. (Auth.)

  19. Establishment of immortal normal and ataxia telangiectasia fibroblast cell lines by introduction of the hTERT gene

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Hideaki; Fukami, Hiroko; Hayashi, Yuko; Kiyono, Tohru; Ishizaki, Kanji [Aichi Cancer Center, Nagoya (Japan). Research Inst.; Nakatsugawa, Shigekazu; Hamaguchi, Michinari [Nagoya Univ. (Japan). School of Medicine

    2002-06-01

    To establish immortal human cells, we introduced the human catalytic subunit of telomerase (hTERT) gene into skin fibroblast cells obtained from normal and ataxia telangiectasia (AT) individuals of Japanese origin. After hTERT introduction, these cells continue to grow beyond a population doubling number of 200 while maintaining their original radiosensitivity. Inductions of p53, phosphorylation of Serl5 in p53, and induction of p21 by X-ray irradiation in immortal cells derived from normal individual were not affected by the hTERT introduction. Both normal and AT immortal cells exhibited an apparent inhibition of growth as original primary cells when they reached confluence. Karyotype analysis has revealed that they are in a diploid range. These results suggest that cells immortalized by hTERT introduction retain their original characteristics except for immortalization, and that they may be useful for analyzing various effects of radiation on human cells. (author)

  20. Radiosensitivity in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Full text: Radiosensitivity is a major hallmark of the human genetic disorder ataxia-telangiectasia. This hypersensitivity to ionizing radiation has been demonstrated in vitro after exposure of patients to therapeutic thought to be the major factor contculture. Clearly an understanding of the nature of the molecular defect in ataxia-telangiectasia will be of considerable assistance in delineating additional pathways that determine cellular radiosensitivity/radioresistance. Furthermore, since patients with this syndrome are also predisposed to developing a number of leukaemias and lymphomas the possible connection between radiosensitivity and cancer predisposition is of interest. Now that the gene (ATM) responsible for this genetic disease has been cloned and identified, progress is being made in determining the role of the ATM protein in mediating the effects of cellular exposure to ionizing radiation and other forms of redox stress. Proteins such as the product of the tumour suppressor gene p53 and the proto-oncogene c-Abl (a protein tyrosine kinase) have been shown to interact with ATM. Since several intermediate steps in both the p53 and c-Abl pathways, activated by ionizing radiation, are known it will be possible to map the position of ATM in these pathways and describe its mechanism of action. What are the clinical implications of understanding the molecular basis of the defect in ataxia-telangiectasia? As outlined above since radiosensitivity is a universal characteristic of A-T understanding the mechanism of action of ATM will provide additional information or radiation signalling in human cells. With this information it may be possible to sensitize tumour cells to radiation and thus increase the therapeutic benefit of radiotherapy. This might involve the use of small molecules that would interfere with the normal ATM controlled pathways and thus sensitize cells to radiation or alternatively it might involve the efficient introduction of ATM anti-sense c

  1. Radiosensitivity in ataxia-telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Lavin, M.F. [Royal Brisbane Hospital, QLD (Australia). Queensland Institute of Medical Research and The Department of Surgery; Khanna, K.K.; Watters, D. [Royal Brisbane Hospital, QLD (Australia). Queensland Institute of Medical Research

    1998-12-31

    Full text: Radiosensitivity is a major hallmark of the human genetic disorder ataxia-telangiectasia. This hypersensitivity to ionizing radiation has been demonstrated in vitro after exposure of patients to therapeutic thought to be the major factor contculture. Clearly an understanding of the nature of the molecular defect in ataxia-telangiectasia will be of considerable assistance in delineating additional pathways that determine cellular radiosensitivity/radioresistance. Furthermore, since patients with this syndrome are also predisposed to developing a number of leukaemias and lymphomas the possible connection between radiosensitivity and cancer predisposition is of interest. Now that the gene (ATM) responsible for this genetic disease has been cloned and identified, progress is being made in determining the role of the ATM protein in mediating the effects of cellular exposure to ionizing radiation and other forms of redox stress. Proteins such as the product of the tumour suppressor gene p53 and the proto-oncogene c-Abl (a protein tyrosine kinase) have been shown to interact with ATM. Since several intermediate steps in both the p53 and c-Abl pathways, activated by ionizing radiation, are known it will be possible to map the position of ATM in these pathways and describe its mechanism of action. What are the clinical implications of understanding the molecular basis of the defect in ataxia-telangiectasia? As outlined above since radiosensitivity is a universal characteristic of A-T understanding the mechanism of action of ATM will provide additional information or radiation signalling in human cells. With this information it may be possible to sensitize tumour cells to radiation and thus increase the therapeutic benefit of radiotherapy. This might involve the use of small molecules that would interfere with the normal ATM controlled pathways and thus sensitize cells to radiation or alternatively it might involve the efficient introduction of ATM anti-sense c

  2. T-cell ALL in ataxia telangiectasia cured with only 7 weeks of anti-leukemic therapy

    DEFF Research Database (Denmark)

    Hersby, Ditte S; Sehested, Astrid; Kristensen, Kim;

    2015-01-01

    A 20-month-old girl diagnosed with T-cell acute lymphoblastic leukemia was treated according to the Nordic NOPHO ALL2000 protocol. The patient developed severe immunosuppression and experienced life-threatening adenovirus infection, which was treated with ribavirin and cidofovir. α-fetoprotein was...... 20- to 30-fold elevated, and genetic analysis confirmed the diagnosis of ataxia telangiectasia. Despite receiving only 7 weeks of anti-leukemic therapy, she has stayed in first remission now 8 years after the diagnosis. We speculate that this could be because of increased chemosensitivity of ATM......-mutated leukemic cells, adenovirus causing a direct oncolytic effect, and/or high levels of endogenous cortisol during her severe infection....

  3. Ataxia-telangiectasia

    OpenAIRE

    Nelson Pires Ferreira

    1983-01-01

    São apresentados os casos de dois irmãos com ataxia-telangiectasia, estudados sob os pontos de vista clínico, eletrencefalográfico, liquórico e encefalográfico. O autor resume os achados de diversos autores e chama a atenção para a regressão parcial da síndrome cerebelar em ambos os pacientes, fato ainda não referido na literatura.

  4. Genetics Home Reference: ataxia-telangiectasia

    Science.gov (United States)

    ... Me Understand Genetics Home Health Conditions ataxia-telangiectasia ataxia-telangiectasia Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Ataxia-telangiectasia is a rare inherited disorder that affects ...

  5. Signal transduction of ataxia-telangiectasia

    International Nuclear Information System (INIS)

    The genetic disorder ataxia-telangiectasia (AT) is characterized by immunodeficiency, progressive cerebellar ataxia, gonadal abnormalities, radiosensitivity, and cancer predisposition. The signal transduction of AT are reviewed, including ATM (AT mutated) gene and clinical symptoms, some transcription factors in the signaling pathway induced by ionizing radiation, cell cycle checkpoint defects, durative oxidative stress and cell apoptosis

  6. Biological and molecular mechanisms of sulfur mustard analogue-induced toxicity in JB6 and HaCaT cells: possible role of ataxia telangiectasia-mutated/ataxia telangiectasia-Rad3-related cell cycle checkpoint pathway.

    Science.gov (United States)

    Tewari-Singh, Neera; Gu, Mallikarjuna; Agarwal, Chapla; White, Carl W; Agarwal, Rajesh

    2010-06-21

    Effective medical treatment and preventive measures for chemical warfare agent sulfur mustard (HD)-caused incapacitating skin toxicity are lacking, because of limited knowledge of its mechanism of action. The proliferating basal epidermal cells are primary major sites of attack during HD-caused skin injury. Therefore, employing mouse JB6 and human HaCaT epidermal cells, here, we investigated the molecular mechanism of HD analogue 2-chloroethyl ethyl sulfide (CEES)-induced skin cytotoxicity. As compared to the control, up to 1 mM CEES treatment of these cells for 2, 4, and 24 h caused dose-dependent decreases in cell viability and proliferation as measured by DNA synthesis, together with S and G2-M phase arrest in cell cycle progression. Mechanistic studies showed phosphorylation of DNA damage sensors and checkpoint kinases, ataxia telangiectasia-mutated (ATM) at ser1981 and ataxia telangiectasia-Rad3-related (ATR) at ser428 within 30 min of CEES exposure, and modulation of S and G2-M phase-associated cell cycle regulatory proteins, which are downstream targets of ATM and ATR kinases. Hoechst-propidium iodide staining demonstrated that CEES-induced cell death was both necrotic and apoptotic in nature, and the latter was induced at 4 and 24 h of CEES treatment in HaCaT and JB6 cells, respectively. An increase in caspase-3 activity and both caspase-3 and poly(ADP-ribose)polymerase (PARP) cleavage coinciding with CEES-caused apoptosis in both cell lines suggested the involvement of the caspase pathway. Together, our findings suggest a DNA-damaging effect of CEES that activates ATM/ATR cell cycle checkpoint signaling as well as caspase-PARP pathways, leading to cell cycle arrest and apoptosis/necrosis in both JB6 and HaCaT cells. The identified molecular targets, quantitative biomarkers, and epidermal cell models in this study have the potential and usefulness in rapid development of effective prophylactic and therapeutic interventions against HD-induced skin toxicity

  7. A derivative of an ataxia-telangiectasia (A-T) cell line with normal radiosensitivity but A-T-like inhibition of DNA synthesis

    International Nuclear Information System (INIS)

    Ataxia-telangiectasia (A-T) cells are hypersensitive to the lethal effects of ionizing radiation and fail to inhibit DNA synthesis following radiation exposure. A cell line derived from an A-T line following DNA-mediated gene transfer has normal radiation sensitivity, but the kinetics of DNA synthesis after γ-irradiation are similar to those of A-T cells. (author)

  8. Ataxia-telangiectasia

    Directory of Open Access Journals (Sweden)

    Nelson Pires Ferreira

    1966-09-01

    Full Text Available São apresentados os casos de dois irmãos com ataxia-telangiectasia, estudados sob os pontos de vista clínico, eletrencefalográfico, liquórico e encefalográfico. O autor resume os achados de diversos autores e chama a atenção para a regressão parcial da síndrome cerebelar em ambos os pacientes, fato ainda não referido na literatura.

  9. An enzyme activity in normal and ataxia telangiectasia cell lines which is involved in the repair of γ-irradiation-induced DNA damage

    International Nuclear Information System (INIS)

    An enzyme that enhances the activity of DNA polymerase I (EC 2.7.7.7) for γ-irradiated calf thymus DNA was demonstrated in cellular extracts of normal human fibroblasts and lymphoid-cell lines. This enzyme was found to be deficient in all cellular extracts of fibroblasts and lymphoid-cell lines examined from patients with the autosomal recessive disease ataxia telangiectasia. The activity in cellular extracts from normal fibroblasts was removed when heated to 1000C for 2 min or when the assay was performed at 40C. No significant deficiency in primer activating enzyme activity was observed in cell-free extracts of lymphoid lines from patients with xeroderma pigmentosum, Huntington's chorea or neurofibromatosis, or from an ataxia telangiectasia heterozygote. (author)

  10. Failure to detect a DNA repair-related defect in the transfection of ataxia-telangiectasia cells by enzymatically restricted plasmid

    International Nuclear Information System (INIS)

    Two SV40-transformed human fibroblast cell lines were transfected with plasmids in which double-strand breaks had been introduced by restriction enzymes, within or near the selected gene. Restriction of pSV2gpt with KpnI reduced the frequency of transfection more in the ionizing radiation-sensitive ataxia-telangiectasia line AT5BIVA than in the resistant line MRC5V1. When the related plasmid pSV2neo was restricted with SmaI, the reduction in transfection was less in the ataxia-telangiectasia than in the normal cells. The apparent defect in transfection of AT5BIVA by pSV2gpt appeared to be a result of the unusual sensitivity of the repair-deficient recipient to the selective agent. Loss of potential transfectants is exacerbated when transient gene expression is reduced by restriction of the plasmid. It is suggested that a reduction in yield of transfectants with restricted plasmid in ataxia-telangiectasia cells cannot readily be used as evidence of a defect in DNA repair. The results are also relevant to standard transfection experiments; they emphasize the importance of optimizing selection when transient expression may be reduced, to ensure that potential transfectants are not killed by the selection regime. (author)

  11. Cell death, chromosome damage and mitotic delay in normal human, ataxia telangiectasia and retinoblastoma fibroblasts after X-irradiation

    International Nuclear Information System (INIS)

    We recently showed (Scott and Zampetti-Bosseler 1980) that X-ray sensitive mouse lymphoma cells sustain more chromosome damage, mitotic delay and spindle defects than X-ray resistant cells. We proposed that (a) chromosome aberrations contribute much more to lethality than spindle defects, and (b) that DNA lesions are less effectively repaired in the sensitive cells and give rise to more G2 mitotic delay and chromosome aberrations. Our present results on human fibroblasts with reported differential sensitivity to ionizing radiation (i.e. normal donors and patients with ataxia telangiectasia and retinoblastoma) support the first hypothesis since we observed a positive correlation between chromosome aberration frequencies and cell killing and no induced spindle defects. Our second hypothesis is however not substantiated since X-ray sensitive fibroblasts from the ataxia patient suffered less mitotic delay than cells from normal donors. A common lesion for mitotic delay and chromosome aberrations can still be assumed by adopting the hypothesis of Painter and Young (1981) that the defect in ataxia cells is not in repair but in a failure of DNA damage to initiate mitotic delay. In contrast to other reports, we found the retinoblastoma cells to be of normal radiation sensitivity (cell killing and aberrations). (author)

  12. Identification of 4 ataxia telangiectasia cell lines hypersensitive to γ-irradiation but not to hydrogen peroxide

    International Nuclear Information System (INIS)

    The effct of hydrogen peroxide on the rate of semi-conservative DNA synthesis in ataxia telangiectasia (AT) and normal human lymphoblastoid cells was investigated. The rate of DNA synthesis in AT cells was not depressed to a lesser extent than in normal cells, as might have been expected since H2O2 is a radiomimetic agent. On the contrary, 4 AT cell lines displayed a higher sensitivity to the inhibitory effect of H2O2 on DNA synthesis than 2 normal cell lines. Comparable levels of cytotoxicity were detected in cell vaibility studies. Furthermore, neither the level of DNA breakage produced by H2O2, nor the rate of repair of these lesions was signigicantly different in normal and AT cells. Together, these results indicate that the AT cell lines utilized in this study are not hypersensitive to the oxidant. It is suggested that H-2-O-2 may not induce lethality via the direct ation of the hydroxyl radical (OH). (Author). 20 refs.; 3 figs.; 1 tab

  13. The radiotoxicity of iodine-125 in ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Normal and ataxia telangiectasia fibroblast strains were labeled with 3H- or 125I-labelled iododeoxyuridine, were stored at -750C to accumulate damage, and were thawed for survival assays. X-ray survival of frozen, unlabeled cells was also determined. The ataxia telangiectasia strains were about twice as sensitive as normal (based upon survival curve slopes) when irradiated with X-rays or 3H decays under frozen conditions. Accumulated 125I decays, while about 13 time more toxic than 3H decays, also killed ataxia telangiectasia cells about twice as efficiently as normal cells. These results indicate that a large proportion of 125I-induced damage - at least 50% - is subject to repair in normal cells. In addition, they suggest that ataxia telangiectasia cells less capably repair a lesion that is induced in common by X-rays and 125I, but in larger proportion by the latter - probably a DNA double-strand break. (Auth.)

  14. Ataxia-telangiectasia cells are not uniformly deficient in poly(ADP-ribose) synthesis following X-irradiation

    International Nuclear Information System (INIS)

    The synthesis of poly(adenosine diphosphoribose [poly(ADP-R)] follows the DNA strand breakage produced by a number of physical and chemical agents, including X-radiation, and may be important for repair of several types of DNA damage. The reduction or abolition of its synthesis following X-irradiation might explain the enhanced sensitivity of ataxia-telangiectasia (A-T) cells to X-ray. We have examined 8 lines of human fibroblasts (including 4 A-T lines) for stimulation of the synthesis of poly(ADP-R) by X-irradiation. Similar amounts of X-ray-stimulated synthesis of poly(ADP-R) were detected in 4 lines of A-T fibroblasts, and in fibrolasts from a xeroderma pigmentosum (XP) patient, a Fanconi's anemia (FA) patient and 2 normal patients. 6 lines of human lymphoblastoid lines were also examined for X-ray-stimulated poly(ADP-R) synthesis. 4 A-T lines displayed an unusually high synthesis of poly(ADP-R) in unirradiated cells compared with 2 normal lines. (orig./AJ)

  15. Ataxia-telangiectasia: future prospects

    OpenAIRE

    Chaudhary MW; Al-Baradie RS

    2014-01-01

    Mohammed Wajid Chaudhary, Raidah Saleem Al-Baradie Pediatric Neurology, Neurosciences Centre, King Fahad Specialist Hospital, Dammam, Kingdom of Saudi Arabia Abstract: Ataxia-telangiectasia (A-T) is an autosomal recessive multi-system disorder caused by mutation in the ataxia-telangiectasia mutated gene (ATM). ATM is a large serine/threonine protein kinase, a member of the phosphoinositide 3-kinase-related protein kinase (PIKK) family whose best-studied function is as master controller of si...

  16. Identification of ataxia telangiectasia heterozygotes, a cancer-prone population, using the single-cell gel electrophoresis (Comet) assay.

    Science.gov (United States)

    Djuzenova, C S; Schindler, D; Stopper, H; Hoehn, H; Flentje, M; Oppitz, U

    1999-06-01

    Heterozygotes of ataxia telangiectasia (AT) may comprise up to 1% of the general population. Because these individuals have no clinical expression of AT but may be highly radiosensitive and strongly predisposed for several forms of cancer, identification of AT carriers represents a considerable interest in cancer epidemiology and radiotherapy. We report a new approach for the in vitro identification of AT-heterozygotes based on the evaluation of the radiosensitivity and DNA damage repair ability of peripheral blood mononuclear cells using the single-cell gel electrophoresis (Comet) assay. The assay was performed on cells isolated from four different groups of individuals: (1) apparently healthy donors (n = 10); (2) patients with breast cancer showing a normal reaction to radiotherapy (n = 10); (3) a group of obligate AT carriers (parents of AT-homozygotes, n = 20); and (4) AT-homozygotes (n = 4). Cells irradiated with 3 Gy of x-rays were assayed for three parameters: (1) the initial and (2) residual DNA damage and (3) the kinetics of DNA damage repair. Both AT-heterozygotes' and AT-homozygotes' cells were found to be highly sensitive to x-irradiation. Quantitative evaluation of the single-cell electrophoregrams revealed that the average initial DNA damage in AT-heterozygous and AT-homozygous cells was almost three times higher than that in control non-AT cells. In addition, the DNA repair process in irradiated AT carrier cells was almost three times slower, and the extent of irreparable DNA damage in these cells was three times greater than in controls. Simultaneous assessment of the three parameters enabled correct identification of all tested AT carriers. This method seems to be a sensitive and useful tool for populational studies as a rapid prescreening test for a mutated AT status. The approach can also be extended for prediction of the in vivo radiosensitivity, which would enable optimization of individual radiotherapy schedules. PMID:10378512

  17. Identification of defective illegitimate recombinational repair of oxidatively-induced DNA double-strand breaks in ataxia-telangiectasia cells

    Science.gov (United States)

    Dar, M. E.; Winters, T. A.; Jorgensen, T. J.

    1997-01-01

    Ataxia-telangiectasia (A-T) is an autosomal-recessive lethal human disease. Homozygotes suffer from a number of neurological disorders, as well as very high cancer incidence. Heterozygotes may also have a higher than normal risk of cancer, particularly for the breast. The gene responsible for the disease (ATM) has been cloned, but its role in mechanisms of the disease remain unknown. Cellular A-T phenotypes, such as radiosensitivity and genomic instability, suggest that a deficiency in the repair of DNA double-strand breaks (DSBs) may be the primary defect; however, overall levels of DSB rejoining appear normal. We used the shuttle vector, pZ189, containing an oxidatively-induced DSB, to compare the integrity of DSB rejoining in one normal and two A-T fibroblast cells lines. Mutation frequencies were two-fold higher in A-T cells, and the mutational spectrum was different. The majority of the mutations found in all three cell lines were deletions (44-63%). The DNA sequence analysis indicated that 17 of the 17 plasmids with deletion mutations in normal cells occurred between short direct-repeat sequences (removing one of the repeats plus the intervening sequences), implicating illegitimate recombination in DSB rejoining. The combined data from both A-T cell lines showed that 21 of 24 deletions did not involve direct-repeats sequences, implicating a defect in the illegitimate recombination pathway. These findings suggest that the A-T gene product may either directly participate in illegitimate recombination or modulate the pathway. Regardless, this defect is likely to be important to a mechanistic understanding of this lethal disease.

  18. Ataxia-telangiectasia: future prospects

    Directory of Open Access Journals (Sweden)

    Chaudhary MW

    2014-09-01

    Full Text Available Mohammed Wajid Chaudhary, Raidah Saleem Al-Baradie Pediatric Neurology, Neurosciences Centre, King Fahad Specialist Hospital, Dammam, Kingdom of Saudi Arabia Abstract: Ataxia-telangiectasia (A-T is an autosomal recessive multi-system disorder caused by mutation in the ataxia-telangiectasia mutated gene (ATM. ATM is a large serine/threonine protein kinase, a member of the phosphoinositide 3-kinase-related protein kinase (PIKK family whose best-studied function is as master controller of signal transduction for the DNA damage response (DDR in the event of double strand breaks (DSBs. The DDR rapidly recognizes DNA lesions and initiates the appropriate cellular programs to maintain genome integrity. This includes the coordination of cell-cycle checkpoints, transcription, translation, DNA repair, metabolism, and cell fate decisions, such as apoptosis or senescence. DSBs can be generated by exposure to ionizing radiation (IR or various chemical compounds, such as topoisomerase inhibitors, or can be part of programmed generation and repair of DSBs via cellular enzymes needed for the generation of the antibody repertoire as well as the maturation of germ cells. AT patients have immunodeficiency, and are sterile with gonadal dysgenesis as a result of defect in meiotic recombination. In the cells of nervous system ATM has additional role in vesicle dynamics as well as in the maintenance of the epigenetic code of histone modifications. Moderate levels of ATM are associated with prolonged lifespan through resistance to oxidative stress. ATM inhibitors are being viewed as potential radiosensitizers as part of cancer radiotherapy. Though there is no cure for the disease at present, glucocorticoids have been shown to induce alternate splicing site in the gene for ATM partly restoring its activity, but their most effective timing in the disease natural history is not yet known. Gene therapy is promising but large size of the gene makes it technically difficult

  19. Pilot study of modified LMB-based therapy for children with ataxia-telangiectasia and advanced stage high grade mature b-cell malignancies

    OpenAIRE

    Sandlund, J.T.; Hudson, M. M.; Kennedy, W; Onciu, M; Kastan, M B

    2013-01-01

    Children with ataxia-telangiectasia (A-T) and cancer have a poorer prognosis due in part to increased treatment-related toxicity. We piloted a curative intent approach in five children with A-T who presented with advanced stage (III, n=2; IV, n=3) B-NHL (diffuse large B-cell lymphoma, n=4; Burkitt leukemia, n=1) using a modified LMB-based protocol. Two achieved sustained CCR (one, CCR at 6 years; one, pulmonary death after 3 years in CCR). Two died from toxicity during induction and 1 failed ...

  20. High-LET Radiation Induced Chromosome Aberrations in Normal and Ataxia Telangiectasia Fibroblast Cells

    Science.gov (United States)

    Kawata, Tetsuya; George, Ms Kerry; Cucinotta, Francis A.; Shigematsu, Naoyuki; Ito, Hisao; Furusawa, Yoshiya; Uno, Takashi

    We investigated the effects of heavy ions beams on chromosomal aberrations in normal and AT cells. Normal and AT fibroblast cells arrested at G0/G1 phase were irradiated with 2 Gy of X-rays, 490 MeV/u Silicon (LET 55 keV/micron), 500 MeV/u Iron (LET 185 keV/micron) and 200 MeV/u Iron (LET 440 keV/micron) particles, and then cells were allowed to repair for 24 hours at 37 degrees before subculture. Calyculin-A induced PCC method was employed to collect G2/M chromosomes and whole DNA probes 1 and 3 were used to analyze chromosomal aberrations such as color-junctions, deletions, simple exchanges (incomplete and reciprocal exchanges) and complex-type exchanges. The percentages of aberrant cells were higher when normal and AT cells were exposed to heavy ions compared to X-rays, and had a tendency to increase with increasing LET up to 185 keV/micron and then decreased at 440 keV/micron. When the frequency of color-junctions per cell was compared after X-ray exposure, AT cells had around three times higher frequency of color-junctions (mis-rejoining) than normal cells. However, at 185 keV/micron there was no difference in the frequency of color-junctions between two cell lines. It was also found that the frequency of simple exchanges per cell was almost constant in AT cells regardless LET levels, but it was LET dependent for normal cells. Interestingly, the frequency of simple exchanges was higher for normal fibroblast cells when it was compared at 185 keV/micron, but AT cells had more complex-type exchanges at the same LET levels. Heavy ions are more efficient in inducing chromosome aberrations in normal and AT cells compared to X-rays, and the aberration types between normal and AT fibroblast appeared different probably due to difference in the ATM gene function.

  1. Cancer Risk-Assessment of Radiation Damage in Ataxia Telangiectasia Heterozygous Human Breast Epithelial Cell Cultures

    Science.gov (United States)

    Applewhite, Lisa C.

    2002-01-01

    This paper describes the study of the markers of cellular changes that are found during the onset of carcinogenesis. Several of the biological factors are markers of stress response, oncoprotein expression, and differentiation factors. Oxidative stress response agents such as heat shock proteins (HSPs) protect cells from oxidative stresses such as ionizing radiation. The onocoprotein HER-2/neu, a specific breast cancer marker, indicates early onset of cancer. Additional structural and morphogenetic markers of differentiation were considered in order to determine initial cellular changes at the initial onset of cancer. As an additional consideration, all-trans retinoic acid (RA), a differentiation agent, was considered because of its known role in regulating normal differentiation and inhibiting tumor proliferation via specific nuclear receptors. This paper discusses study and results of the preliminary analyses of gamma irradiation of AT heterozygous human breast epithelial cells (WH). Comparisons are also made of the effects various RA concentrations post-irradiation.

  2. The oxygen enhancement ratio for radiation lethality in ataxia telangiectasia cells

    International Nuclear Information System (INIS)

    Ataxia telangiectasis (AT) patients are hypersensitive to radiotherapy, and this radiosensitivity is also displayed at a cellular level. The o.e.r. has been determined for X-ray killing in one AT fibroblast line (CRL 1343) known to be defective in DNA repair, and in four presumably normal human fibroblast lines. No significant difference was revealed between the weighted mean of the o.e.r. for AT fibroblasts (2.29 + - 0.11) and that for the four normal cell lines (2.20 + - 0.07). Defective excision of oxygen-independent γ-lesions in CRL 1343 did not therefore alter the ability of oxygen to modify cell killing in this AT line, relative to normal lines. The suggested explanation is that the γ-lesion recognised by M. luteus and defectively excised in this AT line is not a lethal lesion, i.e., the radiation hypersensitivity is not caused by the documented repair defect. (U.K.)

  3. Ataxia-telangiectasia homo- and heterozygous cells show a normal repair and fixation response to anisotonic NaCl treatment after irradiation

    International Nuclear Information System (INIS)

    The effect of anisotonic NaCl treatment on fixation and repair of radiation-induced potentially lethal damage (PLD) was tested in normal human cells and in three homozygous ataxia-telangiectasia (A-T) and two heterozygous A-T cells strains. This effect was observed in both plateau-phase and exponentially growing normal and A-T cells. When an incubation period at 370C was introduced between irradiation and the subsequent anisotonic treatment, recovery was observed in both normal and A-T cells strains. These data show that A-T cells are as proficient as normal cells in repairing PLD that is sensitive to anisotonic NaCl treament. It is proposed that two PLD repair systems may exist, one that is expressed after irradiation in proliferatively arrested cells and another that occurs in plateau-phase as well as exponentially growing cells

  4. Does Ataxia Telangiectasia Mutated (ATM) protect testicular and germ cell DNA integrity by regulating the redox status?

    Science.gov (United States)

    Godschalk, Roger W L; Vanhees, Kimberly; Maas, Lou; Drittij, Marie-Jose; Pachen, Daniëlle; van Doorn-Khosrovani, Sahar van Waalwijk; van Schooten, Frederik J; Haenen, Guido R M M

    2016-08-01

    A balanced redox homeostasis in the testis is essential for genetic integrity of sperm. Reactive oxygen species can disturb this balance by oxidation of glutathione, which is regenerated using NADPH, formed by glucose-6-phosphate dehydrogenase (G6PDH). G6PDH is regulated by the Ataxia Telangiectasia Mutated (Atm) protein. Therefore, we studied the redox status and DNA damage in testes and sperm of mice that carried a deletion in Atm. The redox status in heterozygote mice, reflected by glutathione levels and antioxidant capacity, was lower than in wild type mice, and in homozygotes the redox status was even lower. The redox status correlated with oxidative DNA damage that was highest in mice that carried Atm deletions. Surprisingly, G6PDH activity was highest in homozygotes carrying the deletion. These data indicate that defective Atm reduces the redox homeostasis of the testis and genetic integrity of sperm by regulating glutathione levels independently from G6PDH activity. PMID:27318254

  5. The production and repair of double strand breaks in cells from normal humans and patients with ataxia telangiectasia

    International Nuclear Information System (INIS)

    The production and repair of double strand breaks induced by γ-rays in the DNA of human fibroblasts have been measured by sedimentation in sucrose gradients under non-denaturing conditions. Unirradiated DNA formed a rapidly sedimenting gel. Low doses of radiation released freely sedimenting DNA molecules from this gel. Higher doses reduced the rate of sedimentation of the free DNA due to the introduction of double strand breaks. The breakage efficiency was 1 break/1.3x1010 daltons of DNA/krad. Postirradiation incubation after a high dose of radiation resulted in an increase in molecular weight of the free DNA molecules, and after a low dose the rapidly-sedimenting gel was reformed. These data suggest that double strand breaks are repaired in human fibroblasts. No significant differences were found between fibroblasts from two normal donors and four patients with the radiosensitive disorder, ataxia telangiectasia, in either the production or repair of double strand breaks

  6. Perturbations of cell-cycle progression in γ-irradiated ataxia telangiectasia and Huntington's disease cells detected by DNA flow cytometric analysis

    International Nuclear Information System (INIS)

    The effects of ionizing radiation on cell-cycle progression in lymphoblastoid cell lines derived from ataxia telangiectasia (AT) and Huntington's disease (HD) patients, and from normal individuals, were studied using DNA flow cytometric analysis. A dose of 100 rad γ irradiation blocked a proportion of normal and HD cells in G1. A higher radiation dose applied to normal cells increased the number of cells blocked in G1 and significantly delayed cells which were in S at the time of irradiation from reaching G2 DNA content. The reduced cumulative mitotic index in irradiated cultures of normal cells 2 h after irradiation suggests that cells in G2 at the time of irradiation are delayed before entering mitosis. After irradiation HD cells responded similarly to normal cells except that a greater proportion of HD cells were blocked in G1. AT cells do not show the normal delay in progression from G1 to S, or from S to G2 in the first cycle after irradiation. The cumulative mitotic index was reduced in irradiated cells, implying that they are delayed in G2. Thus AT cells did not recognize or respond to signals from damaged DNA which in normal and HD cells caused a proportional block in G1 and an S-phase delay. The only point of arrest in cell-cycle progression in irradiated AT cells was in G2. (Auth.)

  7. Ataxia telangiectasia: learning from previous mistakes

    OpenAIRE

    Kumar, Naveen; Aggarwal, Puneet; Dev, Nishanth; Kumar, Gunjan

    2012-01-01

    Ataxia telangiectasia is an early onset neurodegenerative disorder. We report a case of childhood onset ataxia and ocular telangiectasia, presenting with pulmonary infection. The patient was diagnosed as ataxia telangiectasia. The patient succumbed to death owing to late diagnosis and sepsis.

  8. Deficient expression of enhanced reactivation of parvovirus H-1 in ataxia telangiectasia cells irradiated with X-rays or u.v. light

    International Nuclear Information System (INIS)

    Cells of patients with ataxia telangiectasia (AT), an inherited disease characterized by a high propensity to cancer, are hypersensitive to ionizing radiation. We investigated whether the hyper-radiosensitivity of AT cells correlated with a defect in their constitutive and/or conditional ability to rescue a damaged exogenous virus. For that purpose, parvovirus H-1, a single-stranded DNA virus whose intranuclear replication mostly relies on host cell functions, was used as a probe. The survival of u.v.-or γ-irradiated H-1 was measured in X-, u.v.-or mock-irradiated human cells of normal (NB-E) or AT (AT5BIVA) origin. γ-Irradiated H-1 survived to similar extents in untreated normal and AT cell lines. Both X- and u.v.-irradiation induced normal cells to achieve an enhanced reactivation (ER) of γ- or u.v.-damaged H-1. In contrast, neither dose-effect curves nor time course revealed significant levels of ER expression after X- or u.v.-irradiation in AT5BIVA cells. Our results suggest that the impairment of ER of damaged parvoviruses may constitute a marker of the AT cell phenotype and be related to the radiosensitivity of AT cells. (author)

  9. Deficient expression of enhanced reactivation of parvovirus H-1 in ataxia telangiectasia cells irradiated with X-rays or u. v. light

    Energy Technology Data Exchange (ETDEWEB)

    Hilgers, G.; Chen, Y.Q.; Cornelis, J.J.; Rommelaere, J.

    1987-02-01

    Cells of patients with ataxia telangiectasia (AT), an inherited disease characterized by a high propensity to cancer, are hypersensitive to ionizing radiation. We investigated whether the hyper-radiosensitivity of AT cells correlated with a defect in their constitutive and/or conditional ability to rescue a damaged exogenous virus. For that purpose, parvovirus H-1, a single-stranded DNA virus whose intranuclear replication mostly relies on host cell functions, was used as a probe. The survival of u.v.- or gamma-irradiated H-1 was measured in X-, u.v.- or mock-irradiated human cells of normal (NB-E) or AT (AT5BIVA) origin. gamma-Irradiated H-1 survived to similar extents in untreated normal and AT cell lines. Both X- and u.v.-irradiation induced normal cells to achieve an enhanced reactivation (ER) of gamma- or u.v.-damaged H-1. In contrast, neither dose-effect curves nor time course revealed significant levels of ER expression after X- or u.v.-irradiation in AT5BIVA cells. Our results suggest that the impairment of ER of damaged parvoviruses may constitute a marker of the AT cell phenotype and be related to the radiosensitivity of AT cells.

  10. Ataxia telangiectasia mutated and Rad3 related (ATR protein kinase inhibition is synthetically lethal in XRCC1 deficient ovarian cancer cells.

    Directory of Open Access Journals (Sweden)

    Rebeka Sultana

    Full Text Available INTRODUCTION: Ataxia telangiectasia mutated and Rad3 Related (ATR protein kinase is a key sensor of single-stranded DNA associated with stalled replication forks and repair intermediates generated during DNA repair. XRCC1 is a critical enzyme in single strand break repair and base excision repair. XRCC1-LIG3 complex is also an important contributor to the ligation step of the nucleotide excision repair response. METHODS: In the current study, we investigated synthetic lethality in XRCC1 deficient and XRCC1 proficient Chinese Hamster ovary (CHO and human ovarian cancer cells using ATR inhibitors (NU6027. In addition, we also investigated the ability of ATR inhibitors to potentiate cisplatin cytotoxicity in XRCC1 deficient and XRCC1 proficient CHO and human cancer cells. Clonogenic assays, alkaline COMET assays, γH2AX immunocytochemistry, FACS for cell cycle as well as FITC-annexin V flow cytometric analysis were performed. RESULTS: ATR inhibition is synthetically lethal in XRCC1 deficient cells as evidenced by increased cytotoxicity, accumulation of double strand DNA breaks, G2/M cell cycle arrest and increased apoptosis. Compared to cisplatin alone, combination of cisplatin and ATR inhibitor results in enhanced cytotoxicity in XRCC1 deficient cells compared to XRCC1 proficient cells. CONCLUSIONS: Our data provides evidence that ATR inhibition is suitable for synthetic lethality application and cisplatin chemopotentiation in XRCC1 deficient ovarian cancer cells.

  11. Human T-lymphotropic virus type 1 p30 interacts with REGgamma and modulates ATM (ataxia telangiectasia mutated) to promote cell survival.

    Science.gov (United States)

    Anupam, Rajaneesh; Datta, Antara; Kesic, Matthew; Green-Church, Kari; Shkriabai, Nikolozi; Kvaratskhelia, Mamuka; Lairmore, Michael D

    2011-03-01

    Human T-lymphotropic virus type 1 (HTLV-1) is a causative agent of adult T cell leukemia/lymphoma and a variety of inflammatory disorders. HTLV-1 encodes a nuclear localizing protein, p30, that selectively alters viral and cellular gene expression, activates G(2)-M cell cycle checkpoints, and is essential for viral spread. Here, we used immunoprecipitation and affinity pulldown of ectopically expressed p30 coupled with mass spectrometry to identify cellular binding partners of p30. Our data indicate that p30 specifically binds to cellular ATM (ataxia telangiectasia mutated) and REGγ (a nuclear 20 S proteasome activator). Under conditions of genotoxic stress, p30 expression was associated with reduced levels of ATM and increased cell survival. Knockdown or overexpression of REGγ paralleled p30 expression, suggesting an unexpected enhancement of p30 expression in the presence of REGγ. Finally, size exclusion chromatography revealed the presence of p30 in a high molecular mass complex along with ATM and REGγ. On the basis of our findings, we propose that HTLV-1 p30 interacts with ATM and REGγ to increase viral spread by facilitating cell survival. PMID:21216954

  12. Cellular radiosensitivity in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Hypersensitivity to both the cell-killing and chromosome-damaging effects of ionizing radiations, and other agents causing DNA breakage, is a consistent feature of cells from individuals with the cancer-prone disorder ataxia-telangiectasia (A-T). Evidence for a defect in DNA strand break rejoining is slight, but a higher-than-normal level of chromosomal breaks persists in irradiated A-T cells. There is also evidence for elevated frequencies of DNA recombination and deletion mutation in A-T cells; these responses may be linked through a loss of fidelity in rejoining DNA breaks through recombination mechanisms. Additionally the regulation of cell-cycle responses is altered in A-T cells: in all phases of the cycle there is some loss of 'checkpoint' function shortly after irradiation, allowing cells to continue cycling despite extensive DNA damage. However, on present evidence, radiation hypersensitivity cannot be explained by this loss of regulatory function. It is suggested that the A-T gene product acts in the early stages of a DNA damage-recognition pathway, normally interacting with regulatory proteins such as p53, but also with proteins involved in the processing of DNA breaks. Reduced efficiency in this type of signalling function could well explain the link between radiosensitivity and cancer proneness. (author)

  13. Dystonia as presenting manifestation of ataxia telangiectasia : a case report.

    OpenAIRE

    Goyal V; Behari M

    2002-01-01

    Ataxia telangiectasia is a genetically inherited multisystem disorder with predominant feature being telangiectasia and cerebellar ataxia. In this report, a family of three siblings suffering from ataxia telangiectasia is described. The proband presented with dystonia and dystonic myoclonus, both of which are rare presenting features of ataxia telangiectasia.

  14. MicroRNA-223 Enhances Radiation Sensitivity of U87MG Cells In Vitro and In Vivo by Targeting Ataxia Telangiectasia Mutated

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Liping; Zhu, Ji [Departments of Radiation Oncology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Zaorsky, Nicholas G. [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania (United States); Deng, Yun [Departments of Radiation Oncology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Wu, Xingzhong [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai (China); Liu, Yong [Departments of Radiation Oncology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Liu, Fangqi; Cai, Guoxiang; Gu, Weilie [Department of Colorectal Cancer, Fudan University, Shanghai Cancer Center, Shanghai (China); Shen, Lijun [Departments of Radiation Oncology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Zhang, Zhen, E-mail: zhenzhang6@hotmail.com [Departments of Radiation Oncology, Fudan University Shanghai Cancer Center, Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China)

    2014-03-15

    Purpose: Ataxia telangiectasia mutated (ATM) protein is important in the DNA damage response because it repairs radiation-induced damage in cancers. We examined the effect of microRNA-223 (miR-223), a regulator of ATM expression, on radiation sensitivity of cancer cells. Methods and Materials: Human embryonic kidney 293 T (293T) cells were infected with pLL3.7-miR-223 plasmid to generate the pLL3.7-miR-223 and -empty virus (EV) lentivirus (miR-223 and EV). A dual luciferase assay in which the reporter contained wild-type 3′ untranslated region (UTR) of ATM was performed. U87MG cells were infected with miR-223 or EV to establish the overexpressed stable cell lines (U87-223 or U87-EV, respectively). Cells were irradiated in vitro, and dose enhancement ratios at 2 Gy (DER{sub 2}) were calculated. Hind legs of BALB/c athymic mice were injected with U87-223 or U87-EV cells; after 2 weeks, half of the tumors were irradiated. Tumor volumes were tracked for a total of 5 weeks. Results: The dual luciferase reporter assay showed a significant reduction in luciferase activity of 293T cells cotransfected with miR-223 and the ATM 3′UTR compared to that in EV control. Overexpression of miR-223 in U87MG cells showed that ATM expression was significantly downregulated in the U87-223 cells compared to that in U87-EV (ATM/β-actin mRNA 1.0 vs 1.5, P<.05). U87-223 cells were hypersensitive to radiation compared to U87-EV cells in vitro (DER{sub 2} = 1.32, P<.01). Mice injected with miR-223-expressing tumors had almost the same tumors after 3 weeks (1.5 cm{sup 3} vs 1.7 cm{sup 3}). However, irradiation significantly decreased tumor size in miR-223-expressing tumors compared to those in controls (0.033 cm{sup 3} vs 0.829 cm{sup 3}). Conclusions: miR-223 overexpression downregulates ATM expression and sensitizes U87 cells to radiation in vitro and in vivo. MicroRNA-223 may be a novel cancer-targeting therapy, although its cancer- and patient-specific roles are

  15. MicroRNA-223 Enhances Radiation Sensitivity of U87MG Cells In Vitro and In Vivo by Targeting Ataxia Telangiectasia Mutated

    International Nuclear Information System (INIS)

    Purpose: Ataxia telangiectasia mutated (ATM) protein is important in the DNA damage response because it repairs radiation-induced damage in cancers. We examined the effect of microRNA-223 (miR-223), a regulator of ATM expression, on radiation sensitivity of cancer cells. Methods and Materials: Human embryonic kidney 293 T (293T) cells were infected with pLL3.7-miR-223 plasmid to generate the pLL3.7-miR-223 and -empty virus (EV) lentivirus (miR-223 and EV). A dual luciferase assay in which the reporter contained wild-type 3′ untranslated region (UTR) of ATM was performed. U87MG cells were infected with miR-223 or EV to establish the overexpressed stable cell lines (U87-223 or U87-EV, respectively). Cells were irradiated in vitro, and dose enhancement ratios at 2 Gy (DER2) were calculated. Hind legs of BALB/c athymic mice were injected with U87-223 or U87-EV cells; after 2 weeks, half of the tumors were irradiated. Tumor volumes were tracked for a total of 5 weeks. Results: The dual luciferase reporter assay showed a significant reduction in luciferase activity of 293T cells cotransfected with miR-223 and the ATM 3′UTR compared to that in EV control. Overexpression of miR-223 in U87MG cells showed that ATM expression was significantly downregulated in the U87-223 cells compared to that in U87-EV (ATM/β-actin mRNA 1.0 vs 1.5, P<.05). U87-223 cells were hypersensitive to radiation compared to U87-EV cells in vitro (DER2 = 1.32, P<.01). Mice injected with miR-223-expressing tumors had almost the same tumors after 3 weeks (1.5 cm3 vs 1.7 cm3). However, irradiation significantly decreased tumor size in miR-223-expressing tumors compared to those in controls (0.033 cm3 vs 0.829 cm3). Conclusions: miR-223 overexpression downregulates ATM expression and sensitizes U87 cells to radiation in vitro and in vivo. MicroRNA-223 may be a novel cancer-targeting therapy, although its cancer- and patient-specific roles are currently undefined

  16. The thermal sensitivity of normal and ataxia telangiectasia human fibroblasts

    International Nuclear Information System (INIS)

    Human normal and ataxia telangiectasia (AT) heterozygote and homozygote cell strains were heated at 42.0 and 45.00C to determine their thermal responses. All cell strains had approximately the same thermal sensitivity and were less thermally sensitive than Chinese hamster cells or many other rodent cell lines reported in the literature. No shoulders were observed on the survival curves for heating at 42.0 or 45.00C. Thermal tolerance developed in both the normal and AT cells strains with heating for prolonged intervals at 42.0GAMMA

  17. DNA repair enzyme deficiency and in vitro complementation of the enzyme activity in cell-free extracts from ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Three ataxia telangiectasia homozygotes, one heterozygote and normal fibroblast strains were compared as to the capacity of their cellular extracts to enhance the priming activity of gamma-irradiated colicin E1 DNA for purified DNA polymerase (EC 2.7.7.7) of Escherichia coli. It was found that homozygotes had substantially lower activity than normal strains, while no difference was detected between the heterozygote and normal strains. In vitro complementation of the activity occurred between extracts of certain strains of homozygotes, allocating them to two complementation groups. (Auth.)

  18. Enhanced sensitivity to camptothecin in ataxia-telangiectasia cells and its relationship with the expression of DNA topoisomerase I

    International Nuclear Information System (INIS)

    The drug Camptothecin induced a marked cell cycle block in G2 phase, the magnitude of the block being closely related to cell kill xeroderma pigmentosum (XP) group A cells showed normal sensitivity to CPT, whereas ataxia-telangiectasis (A-T) derived cells were consistently hypersensitive (3-5 fold) in a manner which could not be related to a primary deficiency in topoisomerase I activity, abnormal capacity for complex formation or anomalies in the intracellular generation of DNA strand breaks. A CPT-resistant A-T subline had reduced topoisomerase I activity but retained the characteristic of hypersensitivity to X-radiation. The subline lost resistance upon in vitro passage with evidence that resistance was initially an unstable feature of a subpopulation of cells. The findings have implications for the role of topoisomerase I in the in vitro phenotype of A-T cells, and the contribution made by topoisomerase I-dependent damage to the cytotoxic action of CPT. (author)

  19. Normal repair of DNA single-strand breaks in patients with ataxia telangiectasia

    International Nuclear Information System (INIS)

    The repair of DNA single-strand breaks induced by X-rays or bleomycin was investigated in diploid fibroblasts isolated from normal individuals and from patients with ataxia telangiectasia by the technique of alkaline elution. No difference was observed between these cell strains in the rate of rejoining of DNA strand breaks induced by low or moderate doses of X-rays or by treatment with bleomycin. Owing to the sensitivity of the technique employed, the possibility that ataxia telangiectasia cells are deficient in DNA single-strand break repair appears unlikely. (Auth.)

  20. [Ataxia telangiectasia: review of 13 new cases].

    Science.gov (United States)

    Valbuena, O; Póo, P; Campistol, J; Vernet, A; Fernández-Alvarez, E; Sierra, I; Gean, E

    1996-01-01

    We report the review of 13 patients who were diagnosed of ataxia telangiectasia before 6 years of age. All of them manifested cerebelous ataxia, oculocutaneus telangiectasias (11), sinopulmonary infections (9), dystonia (9), oculomotor apraxia (9) and Burkitt linfoma (1). We analyse the most common presentation of the disease in early stages and the complementary studies performed. The prompt diagnosis allow us a better control of infections, malignant process and finally the possibility of genetic counseling. PMID:8852005

  1. ATM (ataxia-telangiectasia mutated) abnormality and diseases

    International Nuclear Information System (INIS)

    Ataxia-Telangiectasia (A-T) is an autosomal recessive inherited disease due to mutation of ATM gene on chromosome 11q22.3, with major symptoms of ataxia, telangiectasia, immunodeficiency and frequent complication of cancer, and the cells have characters of chromosomal break, high sensitivity to radiation and inappropriate continuation of DNA synthesis after radiation. This review describes past and present studies of ATM functions with clinical features in the following order: Clinical symptoms and epidemiology; ATM gene mutation in A-T patients, mainly by frame-shift (80-90%); ATM, whose gene consisted from 66 exons (150 kb), functions in phosphoinositide-3-kinase related kinase family which protecting cells from stress and integrating their system, at response to DNA double strand break, and in the cell cycle checkpoints at G1/S, S and G2/M phases; ATM nonsense/missense mutations in embryonic cells leading to carcinogenesis and role of ATM in the suppression of carcinogenesis in somatic cells; Chromosomal translocation which relating to carcinogenesis, by functional defect of ATM; and Other functions of ATM in neuronal growth, immunodeficiency, carbohydrate and lipid metabolism, early senescence, and virus infection. ATM is thus an essential molecule to maintain growth and homeostasis. (T.I.)

  2. Cerebral Abnormalities in Adults with Ataxia-Telangiectasia

    OpenAIRE

    Lin, D.D.M.; Barker, P. B.; Lederman, H M; Crawford, T O

    2013-01-01

    Ataxia-telangiectasia, an autosomal recessive disorder caused by defect of the ataxia-telangiectasia mutated gene, is characterized by progressive neurologic impairment with cerebellar atrophy, ocular and cutaneous telangiectasia, immunodeficiency, heightened sensitivity to ionizing radiation and susceptibility to developing lymphoreticular malignancy. Supratentorial brain abnormalities have been reported only rarely. In this study, brain MRI was performed in 10 adults with ataxia-telangiecta...

  3. Leukoencephalopathy after prophylactic radiation for leukaemia in ataxia telangiectasia.

    OpenAIRE

    Eyre, J A; Gardner-Medwin, D; Summerfield, G P

    1988-01-01

    Children with ataxia telangiectasia have a high probability of developing acute lymphoblastic leukaemia, and have increased sensitivity to chemotherapy and irradiation. We report a 51/2 year old boy who had undiagnosed ataxia telangiectasia when he presented with acute lymphoblastic leukaemia. He subsequently developed a chemoradiation induced leukoencephalopathy after conventional central nervous system prophylaxis.

  4. DNA synthesis in ataxia telangiectasia

    OpenAIRE

    Jaspers, Nicolaas

    1985-01-01

    textabstractAfter the discovery that cultured cells from AT patients are hypersensitive to ionizing radiation the suggestion was made that AT-could be the 1 X-ray-analogue 1 of xeroderma pigmentosum. The latter syndrome (XP) is characterized by hypersensitivity to short-wave UV-radiation, caused by a reduced ability to properly remove UV-induced DNA damage. The evidence for a DNA repair defect in AT cells is not as strong as in the case of XP (see section 2.2.5 of this thesis). Different XP p...

  5. DNA synthesis in ataxia telangiectasia

    NARCIS (Netherlands)

    N.G.J. Jaspers (Nicolaas)

    1985-01-01

    textabstractAfter the discovery that cultured cells from AT patients are hypersensitive to ionizing radiation the suggestion was made that AT-could be the 1 X-ray-analogue 1 of xeroderma pigmentosum. The latter syndrome (XP) is characterized by hypersensitivity to short-wave UV-radiation, caused by

  6. Malignancies in pediatric patients with ataxia telangiectasia

    International Nuclear Information System (INIS)

    Background. Patients with ataxia telangiectasia (AT), known to have an inherent increased susceptibility to the development of cancer, may present with malignancies that are unusual for the patient's age, are often difficult to diagnose clinically and radiographically and respond poorly to conventional therapy. Materials and methods. We reviewed the clinical presentation and imaging studies of 12 AT patients who developed malignancies. Results. Eight of the twelve patients developed non-Hodgkin's lymphoma (CNS, thorax, bone), two developed Hodgkin's disease, and two were diagnosed with gastrointestinal mucinous adenocarcinoma. Conclusion. The lymphomas were commonly extra nodal, and infiltrative rather than mass-like. The recognition of the tumors was often delayed due to confusion with the known infectious complications in AT patients. (orig.)

  7. Malignancies in pediatric patients with ataxia telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, R.C.; Berdon, W.E.; Ruzal-Shapiro, C. [Babies and Children`s Hospital of New York, Department of Radiology, NY (United States); Hall, E.J. [Center for Radiological Research, Columbia Univ., New York, NY (United States); Kornecki, A.; Daneman, A. [Hospital for Sick Children, Dept. of Diagnostic Imaging, Toronto, ON (Canada); Brunelle, F. [Groupe-Hospitalier, Necker-Enfants-Malades, Paris (France); Campbell, J.B. [Arnold Palmer Hospital for Children and Women, Dept. of Radiology, Orlando, FL (United States)

    1999-04-01

    Background. Patients with ataxia telangiectasia (AT), known to have an inherent increased susceptibility to the development of cancer, may present with malignancies that are unusual for the patient`s age, are often difficult to diagnose clinically and radiographically and respond poorly to conventional therapy. Materials and methods. We reviewed the clinical presentation and imaging studies of 12 AT patients who developed malignancies. Results. Eight of the twelve patients developed non-Hodgkin`s lymphoma (CNS, thorax, bone), two developed Hodgkin`s disease, and two were diagnosed with gastrointestinal mucinous adenocarcinoma. Conclusion. The lymphomas were commonly extra nodal, and infiltrative rather than mass-like. The recognition of the tumors was often delayed due to confusion with the known infectious complications in AT patients. (orig.) With 8 figs., 1 tab., 12 refs.

  8. Abnormal retention of X-irradiated ataxia-telangiectasia fibroblasts in G2 phase of the cell cycle: cellular RNA content, chromatin stability and the effects of 3-aminobenzamide

    International Nuclear Information System (INIS)

    We have addressed three aspects of the abnormal sensitivity of SV40 transformed ataxia-telangiectasia (A-T) fibroblasts to X-irradiation, namely: (a) the radiogenic perturbations in cell-cycle traverse analysed by flow cytometry; (b) the involvement of 3-aminobenzamide-sensitive processes in cellular recovery in terms of viability and release from G2+M phase delay; and (c) the functional and structural integrity of cells delayed in G2+M phase using acridine orange as a probe for cellular RNA content and chromatin structure. We report that A-T cells show a dose-dependent and survival-related abnormal retention in G2+M phase due to the lack of a recovery process, despite the capacity of such cells to synthesize ribosomal RNA and maintain the structural integrity of chromatin. Evidence is presented that the recovery process is dependent upon poly(ADPribosyl)ation activity in both normal and A-T cells except that in the latter cell type recovery potential is rapidly saturated in terms of X-ray dose. (author)

  9. Hepatitis B virus X stimulates redox signaling through activation of ataxia telangiectasia mutated kinase

    OpenAIRE

    Matsuda, Yasunobu; Sanpei, Ayumi; Wakai, Toshifumi; Kubota, Masayuki; Osawa, Mami; Hirose, Yuki; Sakata, Jun; Kobayashi, Takashi; Fujimaki, Shun; Takamura, Masaaki; Yamagiwa, Satoshi; Yano, Masahiko; Ohkoshi, Shogo; Aoyagi, Yutaka

    2014-01-01

    Hepatitis B virus X (HBX) protein plays a crucial role in carcinogenesis, but its mechanism is unclear. The involvement of ataxia telangiectasia mutated (ATM) kinase in the enhanced redox system was investigated by examining the phosphorylation level of ATM in HBX gene-transfected cells and in transgenic mice following redox system manipulation by treatment with hydrogen peroxide (H2O2) or antioxidant. Western blotting and immunostaining showed that phospho-ATM was significantly increased by ...

  10. Cranial MRI in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    We examined five males with laboratory-confirmed ataxia-telangiectasia (AT), aged 9-28 years, several times by MRI (9 examinations: 5 at 0.15 T, 3 at 0.5 T, 1 at 1.5 T). Intermediate, T1-, T2- and T2*-weighted spin-echo and gradient-echo sequences were performed. All patients showed vermian atrophy, enlarged fourth ventricle and cisterna magna; four showed cerebellar hemisphere atrophy; two enlarged infracerebellar subarachnoid spaces and four patients had sinusitis. No focal areas of abnormal signal were seen in the brain, diffuse high signal was found in the central cerebral white matter of the oldest patient. AT is an important human model of inherited cancer susceptibility and multisystem ageing; as in xeroderma pigmentosum and other ''breakage syndromes'', ionising radiation should be avoided. When imaging is necessary, MRI should be preferred to CT in patients known or suspected to have AT and those with undefined paediatric ataxias of nontraumatic origin. If atrophy of only the cerebellum, especially the vermis, is noted, laboratory research should be performed to confirm the diagnosis of AT. (orig.)

  11. Síndrome de Ataxia-Telangiectasia

    Directory of Open Access Journals (Sweden)

    Amauri Batista da Silva

    1971-06-01

    Full Text Available A ataxia-telangiectasia, doença de Mme. Louis-Bar, é caracterizada pela associação de ataxia cerebelar progressiva, em geral com início na primeira infância, telangiectasas óculo-cutâneas, movimentos coreoatetósicos, tendência a infecções repetidas do sistema respiratório, retardo estaturo-ponderal, demenciação. São mais ou menos freqüentes os tumores do sistema reticuloendotelial. A doença é geralmente familiar, transmitida por genes recessivos, autossômicos, não ligados ao sexo. A alteração bioquímica mais encontrada consiste na diminuição ou ausência completa da fração A das gamaglobulinas, bem como na perturbação das reações de hipersensibilidade retardada. Os AA. relatam o estudo clínico, biológico e pneumencefalográfico de uma criança de 3 anos de idade, apresentando essa enfermidade desde os 18 meses de vida, sem antecedentes familiares.

  12. Cranial MRI in ataxia-telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Sardanelli, F. [Dept. of Radiology, Univ. of Genoa (Italy); Parodi, R.C. [Dept. of Radiology, Univ. of Genoa (Italy); Ottonello, C. [Dept. of Radiology, Univ. of Genoa (Italy); Renzetti, P. [Dept. of Radiology, Univ. of Genoa (Italy); Saitta, S. [Dept. of Radiology, Univ. of Genoa (Italy); Lignana, E. [G. Gaslini Inst., Genoa (Italy); Mancardi, G.L. [Dept. of Neurology, Univ. of Genoa (Italy)

    1995-01-01

    We examined five males with laboratory-confirmed ataxia-telangiectasia (AT), aged 9-28 years, several times by MRI (9 examinations: 5 at 0.15 T, 3 at 0.5 T, 1 at 1.5 T). Intermediate, T1-, T2- and T2{sup *}-weighted spin-echo and gradient-echo sequences were performed. All patients showed vermian atrophy, enlarged fourth ventricle and cisterna magna; four showed cerebellar hemisphere atrophy; two enlarged infracerebellar subarachnoid spaces and four patients had sinusitis. No focal areas of abnormal signal were seen in the brain, diffuse high signal was found in the central cerebral white matter of the oldest patient. AT is an important human model of inherited cancer susceptibility and multisystem ageing; as in xeroderma pigmentosum and other ``breakage syndromes``, ionising radiation should be avoided. When imaging is necessary, MRI should be preferred to CT in patients known or suspected to have AT and those with undefined paediatric ataxias of nontraumatic origin. If atrophy of only the cerebellum, especially the vermis, is noted, laboratory research should be performed to confirm the diagnosis of AT. (orig.)

  13. Defect in radiation signal transduction in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Exposure of mammalian cells to ionizing radiation causes a delay in progression through the cycle at several checkpoints. Cells from patients with ataxia-telangiectasia (A-T) ignore these checkpoint controls postirradiation. The tumour suppressor gene product p53 plays a key role at the G1/S checkpoint preventing the progression of cells into S phase. The induction of p53 by radiation is reduced and/or delayed in A-T cells, which appears to account for the failure of delay at the G1/S checkpoint. We have investigated further this defect in radiation signal transduction in A-T. While the p53 response was defective after radiation, agents that interfered with cell cycle progression such as mimosine, aphidicolin and deprivation of serum led to a normal p53 response in A-T cells. None of these agents caused breaks in DNA, as determined by pulse-field gel electrophoresis, in order to elicit the response. Since this pathway is mediated by protein kinases, we investigated the activity of several of these enzymes in control and A-T cells. Ca+2-dependent and -independent protein kinase C activities were increased by radiation to the same extent in the two cell types, a variety of serine/threonine protein kinase activities were approximately the same and anti-tyrosine antibodies failed to reveal any differences in protein phosphorylation between A-T and control cells. (author)

  14. Some aspects of glutathione metabolism in ataxia-telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Levels of glutathione (GSH) and two enzymes involved in GSH metabolism, glutathione reductase (GR) and glutathione-S-transferase(s) (GST), were measured in four SV40-transformed human fibroblast cell lines. MRC5-V1 and GM0637, derived from normal individuals, had mean GSH levels of 4.2 and 6.5 nmoles/106 cells, respectively. TAT2SF and AT5BIVA, both from ataxia-telangiectasia (A-T) patients, respectively had 6.5 and 4.2 nmol/106 cells, indicating that basal GSH levels were similar in A-T and normal cells. There was some variation in GST activity among the four cell lines but deficiency in this enzyme cannot be associated with radiosensitivity in A-T. When GR activity was measured, A-T cells had approximately 82 per cent of the mean normal activity. Though statistically significant, (P = 0.05), this small deficiency could be due to chance and is unlikely to be responsible for the radiosensitive phenotype of A-T. (author)

  15. Radiation hypersensitivity and radioresistant DNA synthesis in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Patients with the autosomal recessive genetic disease, ataxia-telangiectasia (A-T), are cancer-prone and hypersensitive to the killing effects of ionizing radiation. In an attempt to isolate the gene(s) responsible for the hypersensitivity of A-T cells, they were transfected with normal human DNA in cosmid vectors containing a rescuable marker (G-418 resistance), and revertants to normal sensitivity were isolated and characterized. The failure of radioresistant revertants to demonstrate a reversion of the phenotype, radioresistant DNA synthesis, shows that this feature is dependent on a gene separate from the one conferring resistance to cell killing. Cells from every A-T patient thus far examined demonstrate both hypersensitivity, in terms of radiation-induced cell killing, and radioresistant DNA synthesis. The results reported here, however, show that the former is not a result of the latter, as previously proposed. Moreover, the fact that these two characteristics can be uncoupled obscures the role(s) that either of them plays in the etiology of the disease, or in the development in its other features, including cancer-proneness

  16. Radiation-induced chromosome aberrations in ataxia telangiectasia cells: high frequency of deletions and misrejoining detected by fluorescence in situ hybridization

    Science.gov (United States)

    Kawata, Tetsuya; Ito, Hisao; George, Kerry; Wu, Honglu; Uno, Takashi; Isobe, Kouichi; Cucinotta, Francis A.

    2003-01-01

    The mechanisms underlying the hyper-radiosensitivity of AT cells were investigated by analyzing chromosome aberrations in the G(2) and M phases of the cell cycle using a combination of chemically induced premature chromosome condensation (PCC) and fluorescence in situ hybridization (FISH) with chromosome painting probes. Confluent cultures of normal fibroblast cells (AG1522) and fibroblast cells derived from an individual with AT (GM02052) were exposed to gamma rays and allowed to repair at 37 degrees C for 24 h. At doses that resulted in 10% survival, GM02052 cells were approximately five times more sensitive to gamma rays than AG1522 cells. For a given dose, GM02052 cells contained a much higher frequency of deletions and misrejoining than AG1522 cells. For both cell types, a good correlation was found between the percentage of aberrant cells and cell survival. The average number of color junctions, which represent the frequency of chromosome misrejoining, was also found to correlate well with survival. However, in a similar surviving population of GM02052 and AG1522 cells, induced by 1 Gy and 6 Gy, respectively, AG1522 cells contained four times more color junctions and half as many deletions as GM02052 cells. These results indicate that both repair deficiency and misrepair may be involved in the hyper-radiosensitivity of AT cells.

  17. Molecular basis of ataxia telangiectasia and related diseases

    Institute of Scientific and Technical Information of China (English)

    Lindsay G BALL; Wei XIAO

    2005-01-01

    Ataxia telangiectasia (AT) is a rare human disease characterized by extreme cellular sensitivity to radiation and a predisposition to cancer, with a hallmark of onset in early childhood. Several human diseases also share similar symptoms with AT albeit with different degrees of severity and different associated disorders. While all AT patients contain mutations in the AT-mutated gene (ATM), most other ATlike disorders are defective in genes encoding an MRN protein complex consisting of Mre11, Rad50 and Nbs1. Both ATM and MRN function as cellular sensors to DNA double-strand breaks, which lead to the recruitment and phosphorylation of an array of substrate proteins involved in DNA repair, apoptosis and cell-cycle checkpoints, as well as gene regulation, translation initiation and telomere maintenance. ATM is a member of the family of phosphatidylinositol 3-kinase-like protein kinases (PIKK), and the discovery of many ATM substrates provides the underlying mechanisms of heterologous symptoms among AT patients. This review article focuses on recent findings related to the initial recognition of doublestrand breaks by ATM and MRN, as well as a DNA-dependent protein kinase complex consisting of the heterodimer Ku70/Ku80 and its catalytic subunit DNAPKcs, another member of PIKK. This possible interaction suggests that a much greater complex is involved in sensing, transducing and co-ordinating cellular events in response to genome instability.

  18. Clinical spectrum of ataxia-telangiectasia in adulthood

    NARCIS (Netherlands)

    Verhagen, M. M. M.; Abdo, W. F.; Willemsen, M. A. A. P.; Hogervorst, F. B. L.; Smeets, D. F. C. M.; Hiel, J. A. P.; Brunt, E. R.; van Rijn, M. A.; Krakauer, D. Majoor; Oldenburg, R. A.; Broeks, A.; Last, J. I.; van't Veer, L. J.; Tijssen, M. A. J.; Dubois, A. M. I.; Kremer, H. P. H.; Weemaes, C. M. R.; Taylor, A. M. R.; van Deuren, M.

    2009-01-01

    Objective: To describe the phenotype of adult patients with variant and classic ataxia-telangiectasia (A-T), to raise the degree of clinical suspicion for the diagnosis variant A-T, and to assess a genotype-phenotype relationship for mutations in the ATM gene. Methods: Retrospective analysis of the

  19. Clinical spectrum of ataxia-telangiectasia in adulthood.

    NARCIS (Netherlands)

    Verhagen, M.M.; Abdo, W.; Willemsen, M.A.A.P.; Hogervorst, F.B.L.; Smeets, D.F.C.M.; Hiel, J.A.P.; Brunt, E.R.; Rijn, M.A. van; Majoor Krakauer, D.; Oldenburg, R.A.; Broeks, A.; Last, J.I.; Veer, L.J. van 't; Tijssen, M.A.; Dubois, A.M.; Kremer, H.P.H.; Weemaes, C.M.R.; Taylor, A.M.; Deuren, M. van

    2009-01-01

    OBJECTIVE: To describe the phenotype of adult patients with variant and classic ataxia-telangiectasia (A-T), to raise the degree of clinical suspicion for the diagnosis variant A-T, and to assess a genotype-phenotype relationship for mutations in the ATM gene. METHODS: Retrospective analysis of the

  20. ERS statement on the multidisciplinary respiratory management of ataxia telangiectasia

    NARCIS (Netherlands)

    Bhatt, J.M.; Bush, A.; Gerven, M.; Nissenkorn, A.; Renke, M.; Yarlett, L.; Taylor, M.; Tonia, T.; Warris, A.; Zielen, S.; Zinna, S.; Merkus, P.J.F.M.

    2015-01-01

    Ataxia telangiectasia (A-T) is a rare, progressive, multisystem disease that has a large number of complex and diverse manifestations which vary with age. Patients with A-T die prematurely with the leading causes of death being respiratory diseases and cancer. Respiratory manifestations include immu

  1. Neuropathology in classical and variant ataxia-telangiectasia

    NARCIS (Netherlands)

    Verhagen, Mijke M. M.; Martin, Jean-Jacques; van Deuren, Marcel; Groote, Chantal Ceuterick-de; Weemaes, Corry M. R.; Kremer, Berry H. P. H.; Taylor, Malcolm A. R.; Willemsen, Michel A. A. P.; Lammens, Martin

    2012-01-01

    Ataxia-telangiectasia (A-T) is classically characterized by progressive neurodegeneration, oculocutaneous telangiectasia, immunodeficiency and elevated a-fetoprotein levels. Some patients, classified as variant A-T, exhibit a milder clinical course. In the latter patients extrapyramidal symptoms, in

  2. Complementation of radiation-sensitive Ataxia telangiectasia cells after transfection of cDNA expression libraries and cosmid clones from wildtype cells

    International Nuclear Information System (INIS)

    In this Ph.D.-thesis, phenotypic complementation of AT-cells (AT5BIVA) by transfection of cDNA-expression-libraries was adressed: After stable transfection of cDNA-expression-libraries G418 resistant clones were selected for enhanced radioresistance by a fractionated X-ray selection. One surviving transfectant clone (clone 514) exhibited enhanced radiation resistance in dose-response experiments and further X-ray selections. Cell cycle analysis revealed complementation of untreated and irradiated 514-cells in cell cycle progression. The rate of DNA synthesis, however, is not diminished after irradiation but shows the reverse effect. A transfected cDNA-fragment (AT500-cDNA) was isolated from the genomic DNA of 514-cells and proved to be an unknown DNA sequence. A homologous sequence could be detected in genomic DNA from human cell lines, but not in DNA from other species. The cDNA-sequence could be localized to human chromosome 11. In human cells the cDNA sequence is part of two large mRNAs. 4 different cosmid clones containing high molecular genomic DNA from normal human cells could be isolated from a library, each hybridizing to the AT500-cDNA. After stable transfection into AT-cells, one cosmid-clone was able to confer enhanced radiation resistance both in X-ray selections and dose-response experiments. The results indicate that the cloned cDNA-fragment is based on an unknown gene from human chromosome 11 which partially complements the radiosensitivity and the defective cell cycle progression in AT5BIVA cells. (orig.)

  3. Disorders of Upper Limb Movements in Ataxia-Telangiectasia.

    Directory of Open Access Journals (Sweden)

    Aasef G Shaikh

    Full Text Available Ataxia-telangiectasia is known for cerebellar degeneration, but clinical descriptions of abnormal tone, posture, and movements suggest involvement of the network between cerebellum and basal ganglia. We quantitatively assessed the nature of upper-limb movement disorders in ataxia-telangiectasia. We used a three-axis accelerometer to assess the natural history and severity of abnormal upper-limb movements in 80 ataxia-telangiectasia and 19 healthy subjects. Recordings were made during goal-directed movements of upper limb (kinetic task, while arms were outstretched (postural task, and at rest. Almost all ataxia-telangiectasia subjects (79/80 had abnormal involuntary movements, such as rhythmic oscillations (tremor, slow drifts (dystonia or athetosis, and isolated rapid movements (dystonic jerks or myoclonus. All patients with involuntary movements had both kinetic and postural tremor, while 48 (61% also had resting tremor. The tremor was present in transient episodes lasting several seconds during two-minute recording sessions of all three conditions. Percent time during which episodic tremor was present was greater for postural and kinetic tasks compared to rest. Resting tremor had higher frequency but smaller amplitude than postural and kinetic tremor. Rapid non-rhythmic movements were minimal during rest, but were triggered during sustained arm postures and goal directed arm movements suggesting they are best considered a form of dystonic jerks or action myoclonus. Advancing age did not correlate with the severity of involuntary limb movements. Abnormal upper-limb movements in ataxia-telangiectasia feature classic cerebellar impairment, but also suggest involvement of the network between the cerebellum and basal ganglia.

  4. p53-Mediated apoptosis is the primary cause of radiation sensitivity in ataxia-telangiectasia

    International Nuclear Information System (INIS)

    The autosomal recessive disease ataxia-telangiectasia (A-T) is characterized by ataxia, immune defects, genetic instability and cancer. A cardinal feature of A-T is a marked sensitivity to the killing effects of ionizing radiation. However, repair of DNA damage in A-T cells is grossly normal and the cause of the radiation sensitivity has remained puzzling despite numerous investigations. We now report that p53-mediated apoptosis is primarily responsible for the radiation sensitivity of A-T cells. We exposed representing three different complementation groups as well as two control cell lines to 0, 1.5 and 3 Gy of 250 kv X-radiation. Morphologic changes, the appearance of cells with sub-G1 DNA content and presence of nucleosome ladders in genomic DNA were considered evidence of apoptosis. By all three criteria, apoptosis was detectable in the A-T cells 24-48 hours after irradiation, peaking by 72 hours. In contrast, control cells underwent minimal apoptosis. Similar results were obtained with 24 hours' exposure to 0.25-0.5 ng/ml streptonigrin, a radiomimetic mutagen. Disruption of p53 function in an A-T fibroblast line by transfection of either the dominant-negative p53143ala mutant or an HPV18 E6 gene was associated with acquisition of near-normal drug resistance and radiation-resistance, while transfection and expression of the p53143ala mutant did not affect the streptonigrin sensitivity of a control fibroblast line. Our results support our hypothesis that an unusually low threshold for the activation of p53-mediated apoptosis by DNA damage may be the primary etiology for both in vivo and in vitro mutagen-sensitivity in A-T. These data also suggest an etiology for the neurological deterioration and immune defects seen in A-T patients: inappropriate activation of apoptosis by spontaneous DNA damage

  5. The Development of Ataxia Telangiectasia Mutated Kinase Inhibitors

    Czech Academy of Sciences Publication Activity Database

    Andrs, M.; Kobarecny, J.; Nepovimova, E.; Jun, D.; Hodný, Zdeněk; Moravcová, Simona; Hanzlíková, Hana; Kuca, K.

    2014-01-01

    Roč. 14, č. 10 (2014), s. 805-811. ISSN 1389-5575 R&D Projects: GA MŠk(CZ) CZ.1.07/2.3.00/30.0044 Grant ostatní: MH CZ - DRO (University Hospital Hradec Kralove(CZ) 00179906 Institutional support: RVO:68378050 Keywords : Ataxia telangiectasia mutated * cancer * chemosensitization * DNA damage response Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.903, year: 2014

  6. DNA repair enzymes in Ataxia telangiectasia and Bloom's syndrome fibroblasts

    International Nuclear Information System (INIS)

    Ataxia telangiectasia, Bloom's syndrome and normal fibroblasts were compared as to the capacity of their cellular extracts to enhance the priming activity of γ-irradiated colicin E1 DNA for purified DNA polymerase. It was found that an ataxia strain had substantially lower, and a Bloom's syndrome strain had slightly lower capacity than a normal strain; while the activities of apurinic site specific endonuclease in these extracts were comparable

  7. The effect of ataxia-telangiectasia mutated kinase-dependent hyperphosphorylation of checkpoint kinase-2 on oligodeoxynucleotide 7909 containing CpG motifs-enhanced sensitivity to X-rays in human lung adenocarcinoma A549 cells

    Directory of Open Access Journals (Sweden)

    Liu XQ

    2015-06-01

    Full Text Available Xiaoqun Liu,1,* Xiangdong Liu,2,* Tiankui Qiao,1 Wei Chen,1 Sujuan Yuan1 1Department of Oncology, 2Department of Ophthalmology, Affiliated Jinshan Hospital, Fudan University, Shanghai, People’s Republic of China *These authors contributed equally to this work Objective: The aim of the study reported here was to further investigate the potential effect of ataxia-telangiectasia mutated (ATM kinase-dependent hyperphosphorylation of checkpoint kinase-2 (Chk2 on radiosensitivity enhanced by oligodeoxynucleotide 7909 containing CpG motifs (CpG ODN7909 in human lung adenocarcinoma A549 cells. Methods: In vitro A549 cells were randomly separated into control, CpG, X-ray, CpG+X-ray, ATM kinase-small interfering RNA (siRNA+CpG+X-ray (ATM-siRNA, and Chk2-siRNA+CpG+X-ray (Chk2-siRNA groups. siRNAs were adopted to silence the ATM and Chk2 genes. Expression and phosphorylation of ATM kinase and Chk2 were detected by Western blot assay. Cell colonies were observed under inverted phase-contrast microscopy. Cellular survival curves were fitted using a multi-target single-hitting model. Cell cycle and apoptosis were analyzed by flow cytometry. Results: Expression of ATM kinase and Chk2 was similar among the control, CpG, X-ray, and CpG+X-ray groups. Phosphorylated ATM kinase and Chk2 were significantly increased in the CpG+X-ray group compared with in the X-ray group (t=6.00, P<0.01 and t=3.13, P<0.05, respectively, though these were hardly detected in the control and CpG groups. However, expression of ATM kinase and Chk2 was clearly downregulated in the ATM-siRNA and Chk2-siRNA groups, respectively. Similarly, their phosphorylation levels were also significantly decreased in the ATM-siRNA group (t=14.35, P<0.01 and t=8.46, P<0.01, respectively and a significant decrease in phosphorylated Chk2 was observed in the Chk2-siRNA group (t=7.28, P<0.01 when compared with the CpG+X-ray group. Further, the number of A549 cells at Gap 2/mitotic phase and the apoptosis

  8. Prolonged c-jun expression in irradiated ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Purpose: Ataxia telangiectasia (AT) is an autosomal recessive disorder associated with radiation sensitivity and an increased incidence of leukemia, lymphoma, and some solid tumors. After exposure to ionizing radiation, cells from patients with AT demonstrate an attenuated G1-phase checkpoint. Because c-jun is known to regulate, in part, the exit from G1 and the onset of DNA replication, we analyzed c-jun transcription in irradiated AT fibroblasts. Methods and Materials: AT5BI fibroblasts were irradiated and RNA was extracted and assayed for c-jun expression by Northern blot analysis. Transcriptional regulation of c-jun was evaluated by use of the 5' untranslated region of the jun promoter linked to the chloramphenicol acetyl transferase (CAT) reporter gene. Deletion mutants of the RSRF, SP-1, AP-1, and CCAAT domains within the jun promoter linked to the CAT reporter were transfected into AT5BI cells. Transfectants were irradiated, and CAT expression was quantified. After x-irradiation, nuclear protein binding to CCAAT was evaluated by an electrophoretic mobility shift assay. Results: X-ray-mediated c-jun expression was sustained in AT5BI cells as compared to only transient expression in irradiated normal diploid fibroblasts. Mutation of either the AP-1 or CCAAT domains within the c-jun promoter reduced transcription by 50% and combined deletion of both AP-1 and CCAAT cis-acting elements entirely eliminated radiation-mediated transcriptional activation. Electrophoretic mobility gel shift assay of the nuclear proteins isolated from irradiated AT fibroblasts demonstrated their increased binding to the CCAAT sequence at 30 min after irradiation. Competition for nuclear protein binding to the CCAAT sequence with excess cold CCAAT demonstrated that protein binding to this sequence was specific. These findings were distinct from induction by phorbol esthers in that the RSRF cis-acting element and DNA segments upstream of -132 base pairs do participate in c-jun induction

  9. Bilateral maculopathy in a patient with ataxia telangiectasia.

    Science.gov (United States)

    Gioia, Lauren V; Bonsall, Dean; Moffett, Kathryn; Leys, Monique

    2016-02-01

    We report a case of toxoplasmosis with bilateral maculopathy in a 7-year-old boy diagnosed with ataxia telangiectasia (AT) at age 6. AT manifests as ataxia, apraxia, telangiectasia, and dysarthria. Common ophthalmologic findings in AT include fine conjunctival telangiectasia. Patients also suffer from recurrent sinopulmonary infections; however, serious opportunistic infection is rarely diagnosed. At 8 years of age he developed disseminated Toxoplasma gondii (toxoplasmosis) infection and meningoencephalitis. This ophthalmologic finding and the subsequent toxoplasmosis meningoencephalitis have not been previously reported in AT. PMID:26917084

  10. Possible role of chromatin alteration in the radiosensitivity of ataxia-telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Hittelman, W.N. [Anderson (M.D.) Cancer Center, Houston, TX (United States); Pandita, T.K. [Columbia Univ., New York, NY (United States). Dept. of Radiation Oncology

    1994-12-01

    Cells derived from individuals with ataxia-telangiectasia (A-T) are known to exhibit increased sensitivity to ionizing radiation and certain radiomimetic chemical agents. Here we summarize our findings regarding the role of chromosome damage and repair in this radiosensitivity. Lymphoblastoid cells derived from A-T homozygotes were characterized for initial chromosome (premature chromosome condensation) and DNA (neutral filter elution) damage and repair kinetics in cells from G1 and G2 cell cycle phases. Despite initial levels of DNA damage being similar to normal controls, A-T cells exhibited nearly a two-fold higher initial amount of chromosome damage. Different A-T cell lines exhibited differing chromosome repair capacities compared with control lymphoblastoid cell lines. These results suggest that A-T cells have an altered chromatin structure whereby DNA double-strand breaks are apparently more efficiently converted into chromosome breaks. (author).

  11. Possible role of chromatin alteration in the radiosensitivity of ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Cells derived from individuals with ataxia-telangiectasia (A-T) are known to exhibit increased sensitivity to ionizing radiation and certain radiomimetic chemical agents. Here we summarize our findings regarding the role of chromosome damage and repair in this radiosensitivity. Lymphoblastoid cells derived from A-T homozygotes were characterized for initial chromosome (premature chromosome condensation) and DNA (neutral filter elution) damage and repair kinetics in cells from G1 and G2 cell cycle phases. Despite initial levels of DNA damage being similar to normal controls, A-T cells exhibited nearly a two-fold higher initial amount of chromosome damage. Different A-T cell lines exhibited differing chromosome repair capacities compared with control lymphoblastoid cell lines. These results suggest that A-T cells have an altered chromatin structure whereby DNA double-strand breaks are apparently more efficiently converted into chromosome breaks. (author)

  12. Ataxia-telangiectasia as a model system for studies of radiation protection mechanisms

    International Nuclear Information System (INIS)

    Patients with ataxia-telangiectasia (AT), a human autosomal recessive genetic disease, are uniformly hypersensitive to ionizing radiation as measured by colony-forming ability and by chromosomal aberrations. Obligate heterozygotes, i.e., parents of AT patients, are slightly more radiosensitive than normal humans in terms of both colony-forming ability and chromosomal aberrations formed in G2. Thus, this system not only furnishes a model system to study factors that are responsible for radioresistance in normal human beings, but is also a unique tool for determining the role of gene dosage on radiation-induced cell killing. Because AT cells seem to be hypomutable to ionizing radiation, they also can be used to study the relationship between radiosensitivity and mutability and, therefore, carcinogenesis. Isolation of the defective gene that causes hypersensitivity in AT cells and its counterpart in normal cells should lead to a breakthrough in our understanding of radiation effects and how they can be prevented in human beings

  13. Cellular and molecular response to irradiation in ataxia telangiectasia and in Fanconi's anemia

    International Nuclear Information System (INIS)

    Ataxia telangiectasia (AT) and Fanconi anemia (FA) are recessive genetic diseases featuring chromosomal instability, increased predisposition to cancer and in vitro hypersensitivity to ionizing radiation (AT) or DNA cross-linking agents (FA). Moreover, an in vivo hypersensitivity to γ-rays exposure was reported in both syndromes. Cellular response to irradiation includes growth arrest (cell cycle modification) and cell death (by apoptosis or necrosis). Since it is generally accepted that apoptosis modulates cellular sensitivity to genotoxic stress, it was of interest to investigate the contribution of apoptosis in determining FA and AT responses to DNA Damaging Agents. The results support the contention that the in vivo hypersensitivity to radiation in these syndromes is not related to a higher rate of apoptotic cells but could be to a higher necrotic response triggering inflammatory reactions in the patients affected by this syndromes. (authors)

  14. Recently emerging signaling landscape of ataxia-telangiectasia mutated (ATM) kinase.

    Science.gov (United States)

    Farooqi, Ammad Ahmad; Attar, Rukset; Arslan, Belkis Atasever; Romero, Mirna Azalea; ul Haq, Muhammad Fahim; Qadir, Muhammad Imran

    2014-01-01

    Research over the years has progressively and sequentially provided near complete resolution of regulators of the DNA repair pathways which are so important for cancer prevention. Ataxia-telangiectasia mutated kinase (ATM), a high-molecular-weight PI3K-family kinase has emerged as a master regulator of DNA damage signaling and extensive cross-talk between ATM and downstream proteins forms an interlaced signaling network. There is rapidly growing scientific evidence emphasizing newly emerging paradigms in ATM biology. In this review, we provide latest information regarding how oxidative stress induced activation of ATM can be utilized as a therapeutic target in different cancer cell lines and in xenografted mice. Moreover, crosstalk between autophagy and ATM is also discussed with focus on how autophagy inhibition induces apoptosis in cancer cells. PMID:25169474

  15. Assessment of the radiosensitivity of ataxia-telangiectasia heterozygotes

    International Nuclear Information System (INIS)

    Heterozygotes of ataxia-telangiectasia (AT) can, in certain parts of the world, represent a significant proportion of the population. Epidemiological studies suggest that they are more cancer prone than normal individuals. Fibroblasts of five AT heterozygotes are significantly more sensitive to gamma irradiation (mean D0 = 1.18 Gy) than five normals (mean D0 = 1.49 Gy) although some overlap in response is observed. Experiments designed to maximize differences in survival by allowing a period for the repair of potentially lethal damage (PLD) showed that only one out of five AT heterozygotes was defective in the repair of PLD. This technique does not, therefore, permit an improved discrimination of AT heterozygotes. Two AT heterozygotes were tested for their ability to repair lesions that give rise to micronuclei. Both, like the homozygote, were seen to be defective in this capacity. Defects in the repair of chromosome damage may permit a cellular discrimination of the heterozygotes

  16. ERS statement on the multidisciplinary respiratory management of ataxia telangiectasia.

    Science.gov (United States)

    Bhatt, Jayesh M; Bush, Andrew; van Gerven, Marjo; Nissenkorn, Andreea; Renke, Michael; Yarlett, Lian; Taylor, Malcolm; Tonia, Thomy; Warris, Adilia; Zielen, Stefan; Zinna, Shairbanu; Merkus, Peter J F M

    2015-12-01

    Ataxia telangiectasia (A-T) is a rare, progressive, multisystem disease that has a large number of complex and diverse manifestations which vary with age. Patients with A-T die prematurely with the leading causes of death being respiratory diseases and cancer. Respiratory manifestations include immune dysfunction leading to recurrent upper and lower respiratory infections; aspiration resulting from dysfunctional swallowing due to neurodegenerative deficits; inefficient cough; and interstitial lung disease/pulmonary fibrosis. Malnutrition is a significant comorbidity. The increased radiosensitivity and increased risk of cancer should be borne in mind when requesting radiological investigations. Aggressive proactive monitoring and treatment of these various aspects of lung disease under multidisciplinary expertise in the experience of national multidisciplinary clinics internationally forms the basis of this statement on the management of lung disease in A-T. Neurological management is outwith the scope of this document. PMID:26621971

  17. ERS statement on the multidisciplinary respiratory management of ataxia telangiectasia

    Directory of Open Access Journals (Sweden)

    Jayesh M. Bhatt

    2015-12-01

    Full Text Available Ataxia telangiectasia (A-T is a rare, progressive, multisystem disease that has a large number of complex and diverse manifestations which vary with age. Patients with A-T die prematurely with the leading causes of death being respiratory diseases and cancer. Respiratory manifestations include immune dysfunction leading to recurrent upper and lower respiratory infections; aspiration resulting from dysfunctional swallowing due to neurodegenerative deficits; inefficient cough; and interstitial lung disease/pulmonary fibrosis. Malnutrition is a significant comorbidity. The increased radiosensitivity and increased risk of cancer should be borne in mind when requesting radiological investigations. Aggressive proactive monitoring and treatment of these various aspects of lung disease under multidisciplinary expertise in the experience of national multidisciplinary clinics internationally forms the basis of this statement on the management of lung disease in A-T. Neurological management is outwith the scope of this document.

  18. Unusual and severe disease course in a child with ataxia-telangiectasia.

    NARCIS (Netherlands)

    Meyts, I.; Weemaes, C.M.R.; Wolf-Peeters, C. de; Proesmans, M.; Renard, M.; Uyttebroeck, A.; Boeck, K. de

    2003-01-01

    Ataxia-telangiectasia (AT) is an autosomal recessive syndrome of combined immunodeficiency. Hallmarks of the disease comprise progressive cerebellar ataxia, oculocutaneous telangiectasia, cancer susceptibility and variable humoral and cellular immunodeficiency. We describe a patient with AT presenti

  19. Cutaneous granulomas in ataxia telangiectasia and other primary immunodeficiencies: Reflection of inappropriate immune regulation?

    NARCIS (Netherlands)

    L.Y.T. Chiam (L. Y T); M.M.M. Verhagen (Mijke); A. Haraldsson (Ásgeir); N.M. Wulffraat (Nico); G.J.A. Driessen (Gertjan); M.G. Netea (Mihai); C.M.R. Weemaes (Corry); M.M.B. Seyger (Marieke); M. van Deuren (Marcel)

    2011-01-01

    textabstractBackground: Non-infective cutaneous granulomas with unknown pathogenesis occur in various primary immunodeficiencies (PIDs) including ataxia telangiectasia (A-T). Objective: To find a common immunological denominator in these cutaneous granulomas. Methods: The dermatological and immunolo

  20. The ATM gene and the radiobiology of ataxia-telangiectasia

    International Nuclear Information System (INIS)

    Ataxia-telangiectasia (A-T) is the classic human genetic disease involving severe ionizing radiation sensitivity and as such has been intensely studied by radiation biologists over the years. Unlike its counterpart for UV light sensitivity -xeroderma pigmentosum - A-T has no obvious DNA repair defect; and there has been much speculation as to the mechanism underlying the altered radioresponses associated with this disease. The gene defective in A-T (ATM) has recently been cloned, and its primary coding sequence determined. The primary sequence of the ATM protein suggests that it has some regulatory functions related to cellular radioresponse and maintenance of genomic stability, and shares these functions with a growing family of other proteins in various organisms. At this juncture it is appropriate to review our current knowledge about the radiobiology of A-T and reflect on the possible radiobiological mechanisms that are suggested by the ATM gene itself. This article will attempt briefly to review current knowledge about the radiobiology of A-T and to introduce new speculations about underlying radiobiological mechanisms that are suggested by the primary amino acid sequence of the predicted ATM gene product. (Author)

  1. Clinical and genetic features of ataxia-telangiectasia

    International Nuclear Information System (INIS)

    There are several variants of ataxia-telangiectasia (A-T): classical A-T with marked radiation sensitivity; classical A-T with intermediate levels of radiation sensitivity; mild A-T with intermediate levels of radiation sensitivity; A-T without telangiectasia; A-T without oculomoto apraxia; and A-T with microcephaly. These disorders are probably caused by different allelic mutations, because affected sibs resemble the index patients, and because there is an association of certain haplo-types of 11q22-23 with specific phenotypes. The Nijmegen Breakage Syndrome, with its lack of ataxia, seems on clinical grounds to be a different disorder. Although A-T is almost always inherited as an autosomal recessive, there are some unusual features; an unexpectedly low parental consanguinity rate, an incidence in sibs that is < 0.25, and occurrence of disease in many different races and in the offspring of mixed race unions. Moreover, looking at haplotypes from 63 UK patients, there is a remarkably low incidence of homozygosity. An autosomal recessive condition that is deficient in parental consanguinity, and in homozygosity for the region around the gene, can be explained by J.H. Edwards' hypothesis that homozygosity for alleles at a neighbouring locus are lethal early in embryogenesis. Other possible mechanisms to explain the unusual genetic features are discussed. (author)

  2. Ataxia-telangiectasia: the pattern of cerebellar atrophy on MRI

    International Nuclear Information System (INIS)

    We describe MRI of the brain in 19 patients with ataxia-telangiectasia (AT) and correlate the appearances with the degree of neurologic deficit. We examined 10 male and nine female patients; 17 were aged between 2 and 12 years (mean 8 years) but a woman and her brother were 35 and 38 years old, and had a variant of AT. Ataxia was the first recognized sign of the disease in every patient. We detected the following patterns of cerebellar atrophy: in the youngest patient, aged 2 years, the study was normal; in the five next youngest patients 3-7 years of age, the lateral cerebellum and superior vermis showed the earliest changes of atrophy; and all but one of the other patients had moderate to marked diffuse atrophy of vermis and cerebellar hemispheres. There were 12 patients aged 9 years and above; one, who was normal, was 9 years old. The five patients who at the time of examination were unable to walk all had diffuse atrophy involving both vermis and cerebellar hemispheres. (orig.)

  3. Ataxia-telangiectasia: the pattern of cerebellar atrophy on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Tavani, F. [Department of Radiology, University of Modena (Italy); Zimmerman, R.A.; Gatti, R.; Bingham, P. [Department of Radiology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States); Berry, G.T. [Department of Endocrinology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States); Sullivan, K. [Department of Immunology, Children' s Hospital of Philadelphia, 34th Street and Civic Center Boulevard, PA 19104, Philadelphia (United States)

    2003-05-01

    We describe MRI of the brain in 19 patients with ataxia-telangiectasia (AT) and correlate the appearances with the degree of neurologic deficit. We examined 10 male and nine female patients; 17 were aged between 2 and 12 years (mean 8 years) but a woman and her brother were 35 and 38 years old, and had a variant of AT. Ataxia was the first recognized sign of the disease in every patient. We detected the following patterns of cerebellar atrophy: in the youngest patient, aged 2 years, the study was normal; in the five next youngest patients 3-7 years of age, the lateral cerebellum and superior vermis showed the earliest changes of atrophy; and all but one of the other patients had moderate to marked diffuse atrophy of vermis and cerebellar hemispheres. There were 12 patients aged 9 years and above; one, who was normal, was 9 years old. The five patients who at the time of examination were unable to walk all had diffuse atrophy involving both vermis and cerebellar hemispheres. (orig.)

  4. Clinical and genetic features of ataxia-telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Bundey, S. [Birmingham Maternity Hospital (United Kingdom). Clinical Genetics Unit

    1994-12-01

    There are several variants of ataxia-telangiectasia (A-T): classical A-T with marked radiation sensitivity; classical A-T with intermediate levels of radiation sensitivity; mild A-T with intermediate levels of radiation sensitivity; A-T without telangiectasia; A-T without oculomoto apraxia; and A-T with microcephaly. These disorders are probably caused by different allelic mutations, because affected sibs resemble the index patients, and because there is an association of certain haplo-types of 11q22-23 with specific phenotypes. The Nijmegen Breakage Syndrome, with its lack of ataxia, seems on clinical grounds to be a different disorder. Although A-T is almost always inherited as an autosomal recessive, there are some unusual features; an unexpectedly low parental consanguinity rate, an incidence in sibs that is < 0.25, and occurrence of disease in many different races and in the offspring of mixed race unions. Moreover, looking at haplotypes from 63 UK patients, there is a remarkably low incidence of homozygosity. An autosomal recessive condition that is deficient in parental consanguinity, and in homozygosity for the region around the gene, can be explained by J.H. Edwards` hypothesis that homozygosity for alleles at a neighbouring locus are lethal early in embryogenesis. Other possible mechanisms to explain the unusual genetic features are discussed. (author).

  5. Effect of caffeine on γ-ray induced G2 delay in ataxia telangiectasia

    International Nuclear Information System (INIS)

    Exposure of normal control and ataxia-telangiectasia (A-T) lymphoblastoid cell lines to ionizing radiation gives rise to an increase in the proportion of G2 phase cells. The size and extent of the G2 phase block is greater in A-T cells than in normal cells. Caffeine has a similar overall effect in control and A-T cell lines in reducing the G2 arrest observed after ionizing radiation. While the proportion of cells accumulated in G2 in A-T cells is considerably greater than in controls, addition of caffeine at the time of maximal G2 block brings about a return of G2 phase cell numbers to unirradiated values in 3 hours in both cell types. In normal control cells the caffeine-mediated decrease in G2 cells is reflected by an increase in mitotic cells. These mitotic cells have a higher frequency of chromosome aberrations compared to cells harvested in the absence of caffeine. Similarly in A-T cells addition of caffeine to irradiated cultures, delayed in G2 phase, increased the number of mitotic cells and the frequency of chromosome aberrations. (author)

  6. An aberration in gamma-ray enhanced reactivation of irradiated adenovirus in ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Ataxia telangiectasia (AT) is a rare human genetic disorder which includes a predisposition to lymphoreticular cancers and a hypersensitivity to conventional radiotherapy. Furthermore, AT cells in vitro exhibit a hypersensitivity to ionising radiation that appears to be correlated with an increased frequency of chromosomal aberrations, a resistance of de novo DNA synthesis to inhibition by radiation-induced DNA damage, a reduced mitotic delay and possible defects in DNA repair. A sensitive viral assay has been used to investigate the capacity of gamma-irradiated AT cells to support the replication of undamaged virus, as well as the extent to which the survival of radiation-damaged virus was affected by gamma-irradiation of these host cells prior to infection. The expression of such enhanced reactivation (ER) of both u.v.-irradiated and gamma-irradiated adenovirus type 2 (Ad2) was examined in a variety of normal and AT human fibroblast strains. For immediate infection of normal human fibroblasts, both a decrease in unirradiated virus expression and an increase in ER were observed with increasing gamma-ray dose to the cells. In contrast, AT fibroblasts were found to be deficient in gamma-ray ER of irradiated Ad2, and this defect appeared to be related to a marked relative radioresistance of unirradiated virus expression in AT compared to normal cells. (author)

  7. Regulation of p53 in response to ionizing radiation in ataxia telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    Purpose: An analysis of the structure and expression of p53 in fibroblasts from patients with ataxia telangiectasia (AT) is presented. Methods and Materials: p53 status in primary and SV40 T antigen-transformed AT cell lines was analyzed using immunocytochemistry and by sequencing with the dideoxynucleotide termination method. The expression of p53 transcript was measured by Northern analysis. The kinetics of p53 protein expression and DNA-binding activity were measured at various intervals following irradiation. Results: No mutation of p53 sequences was found in AT cells. Decreased levels of p53 mRNA and protein were observed in AT5BIVA cells compared to other SV40 T antigen-immortalized fibroblasts. Furthermore, DNA-binds binding analysis shows that a fraction of p53 in the nuclear extracts from AT5BIVA is regulated and binds to specific DNA sequence following irradiation. Conclusion: These data provide evidence for a heterogeneity of the p53 function in SV40-transformed AT cells. It also supports the hypothesis that a regulatory mechanism of p53 activity remains in T antigen-expressing cells in response to ionizing radiation damage

  8. The role of the neuro-astro-vascular unit in the etiology of Ataxia Telangiectasia

    Directory of Open Access Journals (Sweden)

    Leenoy eMeshulam

    2012-09-01

    Full Text Available The growing recognition that brain pathologies do not affect neurons only but rather are, to a large extent, pathologies of glial cells as well as of the vasculature opens to new perspectives in our understanding of genetic disorders of the CNS. To validate the role of the neuron-glial-vascular unit in the etiology of genome instability disorders, we report about cell death and morphological aspects of neuro-glia networks and the associated vasculature in a mouse model of Ataxia Telangiectasia (A-T, a human genetic disorder that induces severe motor impairment. We found that AT-mutated protein deficiency was consistent with aberrant astrocytic morphology and alterations of the vasculature, often accompanied by reactive gliosis. Interestingly similar findings could also be reported in the case of other genetic disorders. These observations bolster the notion that astrocyte-specific pathologies, hampered vascularization and astrocyte-endothelium interactions in the CNS could play a crucial role in the etiology of genome instability brain disorders and could underlie neurodegeneration.

  9. A single ataxia telangiectasia gene with a product similar to PI-3 kinase

    Energy Technology Data Exchange (ETDEWEB)

    Savitsky, K.; Bar-Shira, A.; Gilad, S.; Rotman, G.; Ziv, Y.; Vanagaite, L.; Smith, S.; Uziel, T.; Sfez, S.; Ashkenazi, M. [Tel Aviv Univ. (Israel)] [and others

    1995-06-23

    A gene, ATM, that is mutated in the autosomal recessive disorder ataxia telangiectasia (AT) was identified by positional cloning on chromosome 11q22-23. AT is characterized by cerebellar degeneration, immunodeficiency, chromosomal instability, cancer predisposition, radiation sensitivity, and cell cycle abnormalities. The disease is genetically heterogeneous, with four complementation groups that have been suspected to represent different genes. ATM, which has a transcript of 12 kilobases, was found to be mutated in AT patients from all complementation groups, indicating that it is probably the sole gene responsible for this disorder. A partial ATM complementary DNA clone of 5.9 kilobases encoded a putative protein that is similar to several yeast and mammalian phosphatidylinositol-3{prime} kinases that are involved in mitogenic signal transduction, meiotic recombination, and cell cycle control. The discovery of ATM should enhance understanding of AT and related syndromes and may allow the identification of AT heterozygotes, who are at increased risk of cancer. 54 refs., 5 figs., 1 tab.

  10. Role of chromatin structure modulation by the histone deacetylase inhibitor trichostatin A on the radio-sensitivity of ataxia telangiectasia

    International Nuclear Information System (INIS)

    Highlights: • Role of chromatin compaction on chromosomal instability. • Reduced radiation-induced clastogenicity in Ataxia telangiectasia cell lines. • Histone tails hyperacetylation reduces heterochromatin content favouring DSBs repair. - Abstract: At present, a lot is known about biochemical aspects of double strand breaks (DBS) repair but how chromatin structure affects this process and the sensitivity of DNA to DSB induction is still an unresolved question. Ataxia telangiectasia (A-T) patients are characterised by very high sensitivity to DSB-inducing agents such as ionising radiation. This radiosensitivity is revealed with an enhancement of chromosomal instability as a consequence of defective DNA repair for a small fraction of breaks located in the heterochromatin, where they are less accessible. Besides, recently it has been reported that Ataxia Telangiectasia Mutated (ATM) mediated signalling modifies chromatin structure. In order to study the impact of chromatin compaction on the chromosomal instability of A-T cells, the response to trichostatin-A, an histone deacetylase inhibitor, in normal and A-T lymphoblastoid cell lines was investigated testing its effect on chromosomal aberrations, cell cycle progression, DNA damage and repair after exposure to X-rays. The results suggest that the response to both trichostatin-A pre- and continuous treatments is independent of the presence of either functional or mutated ATM protein, as the reduction of chromosomal damage was found also in the wild-type cell line. The presence of trichostatin-A before exposure to X-rays could give rise to prompt DNA repair functioning on chromatin structure already in an open conformation. Differently, trichostatin-A post-treatment causing hyperacetylation of histone tails and reducing the heterochromatic DNA content might diminish the requirement for ATM and favour DSBs repair reducing chromosomal damage only in A-T cells. This fact could suggest that trichostatin-A post

  11. Role of chromatin structure modulation by the histone deacetylase inhibitor trichostatin A on the radio-sensitivity of ataxia telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Meschini, Roberta, E-mail: meschini@unitus.it; Morucci, Elisa; Berni, Andrea; Lopez-Martinez, Wilner; Palitti, Fabrizio

    2015-07-15

    Highlights: • Role of chromatin compaction on chromosomal instability. • Reduced radiation-induced clastogenicity in Ataxia telangiectasia cell lines. • Histone tails hyperacetylation reduces heterochromatin content favouring DSBs repair. - Abstract: At present, a lot is known about biochemical aspects of double strand breaks (DBS) repair but how chromatin structure affects this process and the sensitivity of DNA to DSB induction is still an unresolved question. Ataxia telangiectasia (A-T) patients are characterised by very high sensitivity to DSB-inducing agents such as ionising radiation. This radiosensitivity is revealed with an enhancement of chromosomal instability as a consequence of defective DNA repair for a small fraction of breaks located in the heterochromatin, where they are less accessible. Besides, recently it has been reported that Ataxia Telangiectasia Mutated (ATM) mediated signalling modifies chromatin structure. In order to study the impact of chromatin compaction on the chromosomal instability of A-T cells, the response to trichostatin-A, an histone deacetylase inhibitor, in normal and A-T lymphoblastoid cell lines was investigated testing its effect on chromosomal aberrations, cell cycle progression, DNA damage and repair after exposure to X-rays. The results suggest that the response to both trichostatin-A pre- and continuous treatments is independent of the presence of either functional or mutated ATM protein, as the reduction of chromosomal damage was found also in the wild-type cell line. The presence of trichostatin-A before exposure to X-rays could give rise to prompt DNA repair functioning on chromatin structure already in an open conformation. Differently, trichostatin-A post-treatment causing hyperacetylation of histone tails and reducing the heterochromatic DNA content might diminish the requirement for ATM and favour DSBs repair reducing chromosomal damage only in A-T cells. This fact could suggest that trichostatin-A post

  12. Ataxia telangiectasia: A report of two cousins and review of literature

    Directory of Open Access Journals (Sweden)

    Anjali Sharma

    2011-01-01

    Full Text Available Ataxia telangiectasia (AT is a rare multisystem, neurodegenerative genetic disorder. Due to its wide clinical heterogeneity, it often leads physicians to an incorrect or missed diagnosis, and insight into this rare disease is important. Here is a case report of two cousins from the same family who showed salient characteristic features of AT along with the incidental finding of co-inheritance of hemoglobin E trait. Though both of them were from the same family, they showed differences in the type of humoral immune deficiencies, laboratory findings, and their susceptibility to develop different types of malignancies. One of them developed T cell acute lymphoblastic leukemia, isolated immunoglobulin A deficiency, and normal serum carcinoembryonic antigen (CEA and carbohydrate antigen 19.9 (CA 19.9 levels. He expired at the age of nine years. The other, though a year older, has still got normal blood counts, normal immunoglobulin levels, and elevated serum CEA and CA 19.9 levels. Thus, insight into this disease is very important as AT patients require protection from unnecessary exposure to ionizing radiation to prevent malignancies. Diagnosis of AT allows appropriate genetic counseling for the family.

  13. Common ataxia telangiectasia mutated haplotypes and risk of breast cancer: a nested case–control study

    International Nuclear Information System (INIS)

    The ataxia telangiectasia mutated (ATM) gene is a tumor suppressor gene with functions in cell cycle arrest, apoptosis, and repair of DNA double-strand breaks. Based on family studies, women heterozygous for mutations in the ATM gene are reported to have a fourfold to fivefold increased risk of breast cancer compared with noncarriers of the mutations, although not all studies have confirmed this association. Haplotype analysis has been suggested as an efficient method for investigating the role of common variation in the ATM gene and breast cancer. Five biallelic haplotype tagging single nucleotide polymorphisms are estimated to capture 99% of the haplotype diversity in Caucasian populations. We conducted a nested case–control study of breast cancer within the Nurses' Health Study cohort to address the role of common ATM haplotypes and breast cancer. Cases and controls were genotyped for five haplotype tagging single nucleotide polymorphisms. Haplotypes were predicted for 1309 cases and 1761 controls for which genotype information was available. Six unique haplotypes were predicted in this study, five of which occur at a frequency of 5% or greater. The overall distribution of haplotypes was not significantly different between cases and controls (χ2 = 3.43, five degrees of freedom, P = 0.63). There was no evidence that common haplotypes of ATM are associated with breast cancer risk. Extensive single nucleotide polymorphism detection using the entire genomic sequence of ATM will be necessary to rule out less common variation in ATM and sporadic breast cancer risk

  14. A high frequency of distinct ATM gene mutations in ataxia-telangiectasia

    Energy Technology Data Exchange (ETDEWEB)

    Wright, J.; Teraoka, S.; Concannon, P. [Univ. of Washington School of Medicine, Seattle, WA (United States)] [and others

    1996-10-01

    The clinical features of the autosomal recessive disorder ataxia-telangiectasia (AT) include a progressive cerebellar ataxia, hypersensitivity to ionizing radiation, and an increased susceptibility to malignancies. Epidemiological studies have suggested that AT heterozygotes may also be at increased risk for malignancy, possibly as a consequence of radiation exposure. A gene mutated in AT patients (ATM) has recently been isolated, making mutation screening in both patients and the general population possible. Because of the relatively large size of the ATM gene, the design of screening programs will depend on the types and distribution of mutations in the general population. In this report, we describe 30 mutations identified in a panel of unrelated AT patients and controls. Twenty-five of the 30 were distinct, and most patients were compound heterozygotes. The most frequently detected mutation was found in three different families and had previously been reported in five others. This corresponds to a frequency of 8% of all reported ATM mutations. Twenty-two of the alterations observed would be predicted to lead to protein truncation at sites scattered throughout the molecule. Two fibroblast cell lines, which displayed normal responses to ionizing radiation, also proved to be heterozygous for truncation mutations of ATM. These observations suggest that the carrier frequency of ATM mutations may be sufficiently high to make population screening practical. However, such screening may need to be done prospectively, that is, by searching for new mutations rather than by screening for just those already identified in AT families. 33 refs., 1 fig., 1 tab.

  15. Chemo- and radiosensitivity testing in a patient with ataxia telangiectasia and Hodgkin disease

    NARCIS (Netherlands)

    Tamminga, RYJ; Dolsma, WV; Leeuw, JA; Kampinga, HH

    2002-01-01

    Treatment of Hodgkin disease (HD) in ataxia telangiectasia (AT) patients is hampered by hypersensitivity to radiation and chemotherapy. Most patients die, due to toxicity or rarely, to progressive disease. The authors report on a 9-year-old girl with stage IIA HD and AT She was treated with a tailor

  16. Cognitive and speech-language performance in children with ataxia telangiectasia

    NARCIS (Netherlands)

    Vinck, Anja; Verhagen, Mijke M. M.; van Gerven, Marjo; de Groot, Imelda J. M.; Weemaes, Corry M. R.; Maassen, Ben A. M.; Willemsen, Michel A. A. P.

    2011-01-01

    Objective: To describe cognitive and speech-language functioning of patients with ataxia-telangiectasia (A-T) in relation to their deteriorating (oculo)motor function. Design: Observational case series. Methods: Cognitive functioning, language, speech and oral-motor functioning were examined in eigh

  17. Motor pathway degeneration in young ataxia telangiectasia patients: A diffusion tractography study

    Directory of Open Access Journals (Sweden)

    Ishani Sahama

    2015-01-01

    Conclusions: Whole tract analysis of the corticomotor, corticospinal and somatosensory pathways in ataxia telangiectasia showed significant white matter degeneration along the entire length of motor circuits, highlighting that ataxia–telangiectasia gene mutation impacts the cerebellum and multiple other motor circuits in young patients.

  18. Radiotherapeutic management of medulloblastoma in a pediatric patient with ataxia telangiectasia

    International Nuclear Information System (INIS)

    Ataxia telangiectasia (AT) is a genetic disorder with a predisposition to malignancy. Cells from patients with AT demonstrate an increased sensitivity to ionizing radiation which creates a problem when these patients require treatment for their malignant disease. An eleven-year-old boy with a previous diagnosis of AT was seen in consultation following partial resection of medulloblastoma in the posterior fossa. To estimate how much the conventional radiation dose might have to be reduced, we compared the radiosensitivity of bone marrow myeloid progenitor cells from this patient to that of cells from the marrow of normal individuals, using colony formation in an agar culture assay system as the endpoint (CFU-Cs). Neither radiation dose-survival curve exhibited a shoulder--each displayed an extrapolation number of 0.99. The survival curve of normal cells displayed a steep slope with a D0 of 0.98 Gy (0.83-1.19 Gy, 95% confidence limits); the slope for the AT cells was considerably steeper with a value for D0 of 0.32 Gy (0.29-0.35 Gy). The ratio of D0's indicated that these AT cells were approximately 3X more radiosensitive than normal cells. Based on this, the daily dose was reduced from 1.8 to 0.6 Gy and the radiation was restricted to 25 treatments to the posterior fossa rather than the conventional cranio-spinal treatment. An additional 5 treatments at 1.0 Gy per day were given to the whole brain. The patient's skin responded to these reduced fraction sizes and doses to a similar degree as normal patients' skin following a standard schedule and the patient is doing well nine months after initiation of treatment

  19. Ataxia telangiectasia-mutated kinase deficiency exacerbates left ventricular dysfunction and remodeling late after myocardial infarction.

    Science.gov (United States)

    Daniel, Laura L; Scofield, Stephanie L C; Thrasher, Patsy; Dalal, Suman; Daniels, Christopher R; Foster, Cerrone R; Singh, Mahipal; Singh, Krishna

    2016-08-01

    Ataxia telangiectasia-mutated kinase (ATM), a cell cycle checkpoint protein, is activated in response to DNA damage and oxidative stress. We have previously shown that ATM deficiency is associated with increased apoptosis and fibrosis and attenuation of cardiac dysfunction early (1-7 days) following myocardial infarction (MI). Here, we tested the hypothesis that enhanced fibrosis and apoptosis, as observed early post-MI during ATM deficiency, exacerbate cardiac dysfunction and remodeling in ATM-deficient mice late post-MI. MIs were induced in wild-type (WT) and ATM heterozygous knockout (hKO) mice by ligation of the left anterior descending artery. Left ventricular (LV) structural and functional parameters were assessed by echocardiography 14 and 28 days post-MI, whereas biochemical parameters were measured 28 days post-MI. hKO-MI mice exhibited exacerbated LV dysfunction as observed by increased LV end-systolic volume and decreased percent fractional shortening and ejection fraction. Infarct size and thickness were not different between the two genotypes. Myocyte cross-sectional area was greater in hKO-MI group. The hKO-MI group exhibited increased fibrosis in the noninfarct and higher expression of α-smooth muscle actin (myofibroblast marker) in the infarct region. Apoptosis and activation of GSK-3β (proapoptotic kinase) were significantly lower in the infarct region of hKO-MI group. Matrix metalloproteinase 2 (MMP-2) expression was not different between the two genotypes. However, MMP-9 expression was significantly lower in the noninfarct region of hKO-MI group. Thus ATM deficiency exacerbates cardiac remodeling late post-MI with effects on cardiac function, fibrosis, apoptosis, and myocyte hypertrophy. PMID:27288435

  20. Rejoining of DNA double-strand breaks in human fibroblasts and its impairment in one ataxia telangiectasia and two Fanconi strains

    International Nuclear Information System (INIS)

    Using the technique of neutral elution through polycarbonate filters as a measure of DNA length, and hence of the number of double-strand breaks incurred as a result of radiation damage, we found that normal human fibroblasts rejoin 50% of all breaks within only 3 min (37 degrees C). This fast rejoining was impaired in fibroblasts from one patient with Ataxia telangiectasia and in fibroblasts from two patients with Fanconi's anemia. Also the number of residual breaks after several hours of repair was higher than in control cells. Other cases with the same diseases were normal in their rejoining of double-strand breaks

  1. Congenital malformations and developmental disabilities in ataxia-telangiectasia, Fanconi anemia, and xeroderma pigmentosum families.

    OpenAIRE

    Welshimer, K; Swift, M

    1982-01-01

    Heterozygous carriers of an ataxia-telangiectasia (A-T), Fanconi anemia (FA), or xeroderma pigmentosum (XP) gene may be predisposed to some of the same congenital malformations or developmental disabilities that are common among homozygotes. To test this hypothesis, medical records, death certificates, and questionnaires from 27 A-T families, 25 FA families, and 31 XP families were reviewed. Eleven XP blood relatives (out of 1,100) were found with moderate or severe unexplained mental retarda...

  2. Conjunctival Telangiectasia in a Patient with Ataxia Telangiectasia: A Case Report

    Directory of Open Access Journals (Sweden)

    Özge Pınar Akarsu

    2012-01-01

    Full Text Available The purpose of this paper is to report a 7-year-old patient who developed bilateral conjunctival hyperemia while being under treatment of pneumonia in Pediatric Infectious Diseases Clinic at Sisli Etfal Training and Research Hospital. Ophthalmological examination revealed bilateral conjunctival telangiectasias which were thought to be the ophthalmologic sign of ataxia telangiectasia after considering the other clinical findings, laboratory and imaging results, and family history. (Turk J Oph thal mol 2012; 42: 75-7

  3. Ataxia telangiectasia mutated (Atm) is not required for telomerase-mediated elongation of short telomeres

    OpenAIRE

    Feldser, David; Strong, Margaret A.; Greider, Carol W

    2006-01-01

    Telomerase-mediated telomere addition counteracts telomere shortening due to incomplete DNA replication. Short telomeres are the preferred substrate for telomere addition by telomerase; however, the mechanism by which telomerase recognizes short telomeres is unclear. In yeast, the Ataxia telangiectasia mutated (Atm) homolog, Tel1, is necessary for normal telomere length regulation likely by altering telomere structure, allowing telomerase recruitment to short telomeres. To examine the role of...

  4. Cutaneous granulomas in ataxia telangiectasia and other primary immunodeficiencies: Reflection of inappropriate immune regulation?

    OpenAIRE

    Chiam, L. Y T; Verhagen, Mijke; Haraldsson, Ásgeir; Wulffraat, Nico; Driessen, Gertjan; Netea, Mihai,; Weemaes, Corry; Seyger, Marieke; van Deuren, Marcel

    2011-01-01

    textabstractBackground: Non-infective cutaneous granulomas with unknown pathogenesis occur in various primary immunodeficiencies (PIDs) including ataxia telangiectasia (A-T). Objective: To find a common immunological denominator in these cutaneous granulomas. Methods: The dermatological and immunological features of 4 patients with A-T and cutaneous granulomas were described. The literature on skin granulomas in A-T and in other PIDs is reviewed. Results: All 4 A-T patients had progressive gr...

  5. Bladder Wall Telangiectasia in a Patient with Ataxia-Telangiectasia and How to Manage?

    OpenAIRE

    Fatma Deniz Aygün; Serdar Nepesov; Haluk Çokuğraş; Yıldız Camcıoğlu

    2015-01-01

    Ataxia-telangiectasia (A-T) is a rare neurodegenerative, inherited disease causing severe morbidity. Oculocutaneous telangiectasias are almost constant findings among the affected cases as telangiectasia is considered the main clinical finding for diagnosis. Vascular abnormalities in organs have been reported infrequently but bladder wall telangiectasias are extremely rare. We aimed to report recurrent hemorrhage from bladder wall telangiectasia in a 9-year-old boy with A-T who had received i...

  6. Conjunctival Telangiectasia in a Patient with Ataxia Telangiectasia: A Case Report

    OpenAIRE

    Özge Pınar Akarsu; Cemile Üçgül Atılgan; Dilek Güven

    2012-01-01

    The purpose of this paper is to report a 7-year-old patient who developed bilateral conjunctival hyperemia while being under treatment of pneumonia in Pediatric Infectious Diseases Clinic at Sisli Etfal Training and Research Hospital. Ophthalmological examination revealed bilateral conjunctival telangiectasias which were thought to be the ophthalmologic sign of ataxia telangiectasia after considering the other clinical findings, laboratory and imaging results, and family history. (Tu...

  7. The response of normal and ataxia-telangiectasia human fibroblasts to the lethal effects of far, mid and near ultraviolet radiations

    International Nuclear Information System (INIS)

    The responses of two ataxia-telangiectasia (A-T) cell strains to the lethal effects of monochromatic far, mid and near ultraviolet radiations have been determined and compared with the responses of three normal human cell strains. The authors results confirm a previous observation that the A-T cell strain AT4BI is abnormally sensitive to the lethal effects of mid u.v. (313 nm) radiation. After far u.v. (254 nm) radiation the strain AT4BI exhibits a small but statistically significant increase in sensitivity compared to the normal strains. Of most interest, in terms of a mechanistic interpretation of the sensitivity of A-T strains, the survival responses of neither A-T strain tested to near u.v. (365 nm) radiation differed significantly from the mean response of the normal strains, although it is of interest that one normal strain (48BR) was found to be significantly more resistant to near u.v. radiation than any of the other strains tested. The results are discussed in terms of the possible induction of radiogenic lesions in DNA by ultraviolet radiations and the possible mechanisms of radiation sensitivity in ataxia-telangiectasia. (author)

  8. Prenatal diagnosis of ataxia-telangiectasia and Nijmegen Breakage Syndrome by the assay of radioresistant DNA synthesis

    International Nuclear Information System (INIS)

    Prenatal diagnosis was performed in 16 pregnancies at risk of ataxia-telangiectasia (A-T) or Nijmegen Breakage Syndrome (NBS). Radioresistant DNA synthesis (RDS) was investigated in cultured chorionic villus (CV) cells and/or amniotic fluid (AF) cells. In four pregnancies, an affected foetus was diagnosed with increased RDS in cultured CV cells. In three of the four cases confirmation of the diagnosis was obtained by analysis of AF cells and/or skin fibroblasts from the foetus cultured after termination of the pregnancy; in the fourth case a fibroblast culture from the aborted foetus failed. In one case, only AF cells could be analysed in a late stage of pregnancy; pregnancy was terminated due to intermediate/equivocal results but the foetus fibroblasts showed normal RDS. Normal RDS was demonstrated in the other 11 pregnancies at 25% risk either by analysis of CB cells (nine cases) or of AF cells (two cases). In some cases the (normal) results on the CV cells were corroborated by subsequent analysis of Af cells. The results suggest that RDS analysis of CV cells allows reliable prenatal diagnosis of A-T/NBS. However, amniocentesis may be necessary to confirm normal results on CV cells if the foetus is female (because of the risk of maternal cell contamination) or in the rare case of equivocal results. (author)

  9. The effect of caffeine on X-ray-induced mitotic delay in normal human and ataxia-telangiectasia fibroblasts

    International Nuclear Information System (INIS)

    The authors previously showed that radiation-sensitive fibroblasts from ataxia-telangiectasia (A-T) patients sustain less G2 delay after X-irradiation than normal fibroblasts. Caffeine is known to reduce the amount of X-ray-induced delay in various mammalian cell types. It is proposed that A-T cells have an altered chromatin structure, similar to that of caffeine-treated normal cells and that this results in a failure of A-T cells to delay their progression through the cell cycle to allow time for DNA repair. The authors now show that caffeine treatment after X-irradiation reduces G2 delay in both A-T and normal cells. The authors confirm the results previously obtained on lymphocytes that caffeine potentiates the chromosome-damaging effects of X-rays in both A-T and normal fibroblasts. These and other data suggest that the radiation responses of A-T cells and of caffeine-treated normal cells are caused by different mechanisms. (Auth.)

  10. Radio-induced apoptosis is impaired in individuals homozygous and heterozygous for the ataxia-telangiectasia gene(s)

    International Nuclear Information System (INIS)

    Ataxia-telangiectasia is a progressive recessive disease featuring neuro degeneration, immunodeficiency, chromosomal instability, radiation hypersensitivity and increased predisposition to cancer. Impaired induction of the tumor suppressor protein p53 after γ-irradiation was recently reported. All together these characteristics may be compatible with an inability to correctly regulate the apoptotic pathway of cell death in this syndrome. We show here that lymphocyte cultures from AT patients are characterized by a 3 times more elevated spontaneous level of apoptotic cells compared to normal ones. In spite of this, 24 h after exposure to γ-irradiation (5 to 10 Gy), AT lymphocytes show a dramatically reduced capacity to undergo apoptosis compared to normal cells. We obtained similar results on EBV-transformed lymphoblasts. Interestingly, lymphoblasts from obligate heterozygous for the AT mutation(s) show the same features as AT lymphoblasts, i.e. an elevated frequency of spontaneous and a reduced level of radio-induced apoptotic figures in comparison to normal cultured cells. In conclusion, we show here, for the first time, that mutation(s) in AT gene(s) results in an impaired ability to correctly regulate the apoptotic pathway of cell death. (author). 26 refs., 4 figs., 2 tabs

  11. Radiation-induced G2 delay and spontaneous chromosome aberrations in ataxia-telangiectasia homozygotes and heterozygotes

    International Nuclear Information System (INIS)

    The extent of cell cycle delay of lymphocytes X-irradiated in G2 phase was measured by mitotic inhibition determinations in 66 controls, 14 ataxia-telangiectasia (A-T) homozygotes and 27 obligate heterozygotes. Homozygotes had a significantly reduced mitotic index (MI) in unirradiated samples and showed significantly less radiation-induced mitotic inhibition than controls. This confirms our earlier disputed observations on A-T fibroblasts and demonstrates a G2 checkpoint defect in addition to the well-known defects in S phase and at the G1-S phase transition. There are two separate and opposite abnormal G2 responses of A-T cells; a primary event in which cells in G2 at the time of irradiation suffer less delay than controls, and a secondary event in which cells irradiated at earlier stages of the cycle are more delayed when they pass into G2. The MI of unirradiated heterozygote cells and the extent of mitotic inhibition were indistinguishable from controls. Spontaneous unstable chromosome aberrations were, as previously reported, significantly higher in homozygotes than in controls. (author)

  12. Proceedings of the fourteenth international workshop on Ataxia-Telangiectasia: abstracts. V.1

    International Nuclear Information System (INIS)

    Research in the area of Ataxia-Telangiectasia (A-T) has made considerable progress in the last several years, providing a good understanding of both the disease and the underlying problem of maintaining genomic integrity. Many scientific and medical institutions in India have focused on these research areas with most investigators utilizing genetic and molecular biology tools for diagnostic purposes. Moreover, many medical professionals are also actively engaged in clinical practices as well as research in the area of Ataxia and related neurological disorders. DNA damage, cancer and neurodegenerative diseases are most discussed areas in the workshop. Papers relevant to INIS are indexed separately

  13. A Precocious Cerebellar Ataxia and Frequent Fever Episodes in a 16-Month-Old Infant Revealing Ataxia-Telangiectasia Syndrome

    Directory of Open Access Journals (Sweden)

    Luigi Nespoli

    2013-01-01

    Full Text Available Ataxia-telangiectasia (AT is the most frequent progressive cerebellar ataxia in infancy and childhood. Immunodeficiency which includes both cellular and humoral arms has variable severity. Since the clinical presentation is extremely variable, a high clinical suspicion will allow an early diagnosis. Serum alpha-fetoprotein is elevated in 80–85% of patients and therefore could be used as a screening tool. Here, we present a case of a 5-year-old female infant who was admitted to our department at the age of 16 months because of gait disorders and febrile episodes that had begun at 5 months after the cessation of breastfeeding. Serum alfa-fetoprotein level was elevated. Other investigations showed leukocytopenia with lymphopenia, reduced IgG2 and IgA levels, and low titers of specific postimmunization antibodies against tetanus toxoid and Haemophilus B polysaccharide. Peripheral lymphocytes subsets showed reduction of T cells with a marked predominance of T cells with a memory phenotype and a corresponding reduction of naïve T cells; NK cells were very increased (41% with normal activity. The characterization of the ATM gene mutations revealed 2 specific mutations (c.5692C > T/c.7630-2A > C compatible with AT diagnosis. It was concluded that AT syndrome should be considered in children with precocious signs of cerebellar ataxia and recurrent fever episodes.

  14. Gastric outlet obstruction due to adenocarcinoma in a patient with Ataxia-Telangiectasia syndrome: a case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Hammond Sue

    2009-03-01

    Full Text Available Abstract Background Ataxia-Telangiectasia syndrome is characterized by progressive cerebellar dysfunction, conjuctival and cutaneous telangiectasias, severe immune deficiencies, premature aging and predisposition to cancer. Clinical and radiographic evaluation for malignancy in ataxia-telangiectasia patients is usually atypical, leading to delays in diagnosis. Case presentation We report the case of a 20 year old ataxia-telangiectasia patient with gastric adenocarcinoma that presented as complete gastric outlet obstruction. Conclusion A literature search of adenocarcinoma associated with ataxia-telangiectasia revealed 6 cases. All patients presented with non-specific gastrointestinal complaints suggestive of ulcer disease. Although there was no correlation between immunoglobulin levels and development of gastric adenocarcinoma, the presence of chronic gastritis and intestinal metaplasia seem to lead to the development of gastric adenocarcinoma. One should consider adenocarcinoma in any patient with ataxia-telangiectasia who presents with non-specific gastrointestinal complaints, since this can lead to earlier diagnosis.

  15. Two-tier analysis of histone H2AX phosphorylation allows the identification of Ataxia Telangiectasia heterozygotes

    International Nuclear Information System (INIS)

    Background and purpose: Ataxia Telangiectasia (A-T) heterozygotes constitute 0.36-1% of the general population. They have a higher risk of developing several types of cancer and may be more likely to suffer side-effects following radiotherapy than the general population. Their identification is both labor- and time-consuming and the sensitivity and specificity of the methods employed has not been evaluated. This paper describes a new approach to the identification of A-T heterozygotes based on a two-tier analysis of histone H2AX phosphorylation. Materials and methods: We compared the T-cell phenotype after exposure to 2 Gy in nine obligate A-T heterozygotes and 17 normal donors. Examined end points were histone H2AX phosphorylation by flow cytometry 1 h after irradiation (kinase proficiency) and the residual γ-H2AX foci by confocal microscopy 72 h after irradiation (DSB repair proficiency). Results: The sequential use of these two methods results in 100% positive predictive value (PPV), 67% negative predictive value (NPV), 78% sensitivity, and 100% specificity. The overall hit rate, i.e. the ratio between the true positives plus the true negatives and the total number of observations was 85%. Conclusions: A-T heterozygotes can be identified by analysing irradiated T-cell H2AX phosphorylation level and residual γ-H2AX foci.

  16. Relationship between Ataxia Telangiectasia Mutant(ATM) Expression of HL-60 and SiHA Cell Lines and Their Cell Cycle Arrest after 60Co Radiation%HL-60和SiHA细胞株ATM表达量与60Co照射后细胞周期阻滞之间的关系

    Institute of Scientific and Technical Information of China (English)

    汤屹; 刘文励; 周剑锋; 高庆蕾; 吴剑宏

    2003-01-01

    背景与目的:毛细血管扩张性共济失调综合征( ataxia telangiectasia,AT)是由 ATM( ataxia telangiectasia mutant)基因所致,其突出特点是对放射线非常敏感,因此, ATM表达与放射敏感性应存在相关性.本研究旨在探讨两种肿瘤细胞株 ATM表达量与 60Co照射后细胞周期阻滞功能之间的关系.方法:使用半定量 RT-PCR和流式细胞仪技术检测 HL-60细胞和 SiHA细胞中 ATM mRNA和 ATM蛋白表达量,同时以 6、 10和 15 Gy 60Co照射 SiHA细胞, HL 60细胞仅以 6、 10 Gy照射,于照射后 6、 12、 24、 48及 60 h观察细胞周期阻滞现象和细胞凋亡率的变化.结果: HL 60细胞 ATM平均蛋白荧光强度为 14.11±2.38, SiHA细胞为 27.74± 1.16,约为 HL-60细胞的 2倍; HL-60细胞 ATM mRNA相对表达量为 0 .09, SiHA细胞为 0.80,约为 HL-60细胞的9倍.照射后 HL-60细胞和 SiHA细胞均表现 G2/M期阻滞.射线对 HL-60细胞周期阻滞功能明显较 SiHA细胞弱.结论:放射线对 HL-60细胞和 SiHA细胞的周期阻滞功能与 ATM表达量相符,即 ATM表达量低,细胞周期阻滞功能差.

  17. Potentiation by caffeine of x-ray damage to cultured human skin fibroblasts from normal subjects and ataxia-telangiectasia patients

    International Nuclear Information System (INIS)

    Caffeine was found to potentiate x-ray-induced killing of human diploid fibroblasts from a normal subject and an ataxia-telangiectasia (AT) patient when it was present at 2 mM concentration for 30 to 66 h postirradiation. The dose-modifying factor for caffeine-treated normal cells had an average value of 1.26 +- 0.13 which did not vary significantly with treatment time or x-ray dose. The dose-modifying factor for caffeine-treated AT cells was 1.12 +- 0.12 at 30 h, rose to 1.66 +- 0.17 at 41 h, and decreased to 1.31 +- 0.13 at 66 h. Thus no clear difference was observed between these two cell strains' susceptibility to postirradiation caffeine treatment

  18. The potentiation by caffeine of X-ray damage to cultured human skin fibroblasts from normal subjects and ataxia-telangiectasia patients

    International Nuclear Information System (INIS)

    Caffeine was found to potentiate X-ray-induced killing of human diploid fibroblasts from a normal subject and an ataxia-telangiectasia (AT) patient when it was present at 2 mM concentration for 30 to 66 hr postirradiation. The dose-modifying factor for caffeine-treated normal cells had an average value of 1.26 +/- 0.13 which did not vary significantly with treatment time or X-ray dose. The dose-modifying factor for caffeine-treated AT cells was 1.12 +/- 0.12 at 30 hr, rose to 1.66 +/- 0.17 at 41 hr, and decreased to 1.31 +/- 0.13 at 66 hr. Thus no clear difference was observed between these two cell strains' susceptibility to postirradiation caffeine treatment

  19. Excision repair in ataxia telangiectasia, Fanconi's anemia, Cockayne syndrome, and Bloom's syndrome after treatment with ultraviolet radiation and N-acetoxy-2-acetylaminofluorene

    International Nuclear Information System (INIS)

    Excision repair of damage due to ultraviolet radiation, N-acetoxy-2-acetylaminofluorene and a combination of both agents was studied in normal human fibroblasts and various cells from cancer prone patients (ataxia telangiectasia, Fanconi's anemia, Cockayne syndrome and Bloom's syndrome). Three methods giving similar results were used: unscheduled DNA synthesis by radioautography, photolysis of bromodeoxyuridine incorporated into parental DNA during repair, and loss of sites sensitive to an ultraviolet endonuclease. All cell lines were proficient in repair of ultraviolet and acetoxy acetylaminofluorene damage and at saturation doses of both agents repair was additive. We interpret these data as indicating that the rate limiting step in excision repair of ultraviolet and acetoxy acetylaminofluorene is different and that there are different enzyme(s) working on incision of both types of damages. (Auth.)

  20. DNA-mediated gene transfer into human diploid fibroblasts derived from normal and ataxia-telangiectasia donors: parameters for DNA transfer and properties of DNA transformants

    International Nuclear Information System (INIS)

    An investigation was made of the feasibility of DNA-mediated gene transfer into human diploid fibroblasts derived from patients with the radiation sensitive syndrome ataxia-telangiectasia (A-T) and from a normal donor. Although they are markedly different in their growth characteristics, both normal and A-T strains give similar frequencies for DNA transfer in a model system using the recombinant plasmid pSV2-gpt. pSV2-gpt DNA transformants arise with a frequency between 10-5 and 10-4 per viable cell. Analysis of such transformants, although possible, is severely handicapped by the limited clonal life span of diploid human cells. Despite these problems it may be concluded that diploid human fibroblasts are competent recipients for DNA-mediated gene transfer and the putative repair deficiency of A-T does not markedly effect the efficiency of this process. (author)

  1. Ataxia Telangiectasia

    Science.gov (United States)

    ... the first decade of life. Telangiectasias (tiny, red "spider" veins), which appear in the corners of the ... States? An estimated 1 percent of the U.S. population, or about 2.5 million people, may be ...

  2. Silencing of ataxia-telangiectasia mutated by siRNA enhances the in vitro and in vivo radiosensitivity of glioma.

    Science.gov (United States)

    Li, Yan; Li, Luchun; Li, Bo; Wu, Zhijuan; Wu, Yongzhong; Wang, Ying; Jin, Fu; Li, Dairong; Ma, Huiwen; Wang, Donglin

    2016-06-01

    It is reported that high expression of the ataxia-telangiectasia mutated (ATM) gene is linked with radioresistance in glioma. We hypothesized that the radiosensitivity of this brain tumor is enhanced by silencing of the ATM gene. We transfected the glioma cell line U251 with the siRNA-ATMpuro (group A) lentivirus or the siRNA-HKpuro (group N, negative control) lentivirus before irradiation. RT-qPCR and western blotting were performed to verify the efficiency of siRNA‑mediated ATM silencing. Expression levels of the ATM gene and protein were obviously downregulated after transfection. Moreover, the expression of the p53, PCNA and survivin genes, which are related to radiosensitivity, was also decreased. CCK-8 and colony formation assays showed lower cell proliferation and survival in group A than in groups N and C (control group that was not transfected with any siRNA). The level of double-stranded DNA breaks was also greater in group A, as determined by the comet tail assay. Flow cytometry showed a higher rate of cell apoptosis and a higher number of cells in the G2 phase in group A. Furthermore, caspase-3, caspase-8 and caspase-9 activity was also higher in group A. In vivo analysis in mouse models created by implantation of the transfected cell lines showed that the amount of necrosis and hemorrhage was higher in group A than that in the control groups. In conclusion, silencing of ATM via the siRNA technique could improve the in vitro and in vivo radiosensitivity of glioma cells. PMID:27108486

  3. Congenital malformations and developmental disabilities in ataxia-telangiectasia, Fanconi anemia, and xeroderma pigmentosum families.

    Science.gov (United States)

    Welshimer, K; Swift, M

    1982-09-01

    Heterozygous carriers of an ataxia-telangiectasia (A-T), Fanconi anemia (FA), or xeroderma pigmentosum (XP) gene may be predisposed to some of the same congenital malformations or developmental disabilities that are common among homozygotes. To test this hypothesis, medical records, death certificates, and questionnaires from 27 A-T families, 25 FA families, and 31 XP families were reviewed. Eleven XP blood relatives (out of 1,100) were found with moderate or severe unexplained mental retardation, a significant excess compared to the FA and A-T families (3/1,439). There were four microcephalic XP blood relatives and none in the FA or A-T families. In the A-T families, idiopathic scoliosis and vertebral anomalies were in excess, while genitourinary and distal limb malformations were found in the FA families. A-T, FA, or XP heterozygotes may constitute an important proportion of individuals at risk for specific malformations or developmental abnormalities. PMID:7124732

  4. Bladder Wall Telangiectasia in a Patient with Ataxia-Telangiectasia and How to Manage?

    Directory of Open Access Journals (Sweden)

    Fatma Deniz Aygün

    2015-01-01

    Full Text Available Ataxia-telangiectasia (A-T is a rare neurodegenerative, inherited disease causing severe morbidity. Oculocutaneous telangiectasias are almost constant findings among the affected cases as telangiectasia is considered the main clinical finding for diagnosis. Vascular abnormalities in organs have been reported infrequently but bladder wall telangiectasias are extremely rare. We aimed to report recurrent hemorrhage from bladder wall telangiectasia in a 9-year-old boy with A-T who had received intravenous cyclophosphamide for non-Hodgkin’s lymphoma. Since A-T patients are known to be more susceptible to chemical agents, we suggested that possibly cyclophosphamide was the drug which induced bladder wall injury in this patient.

  5. A haplotype common to intermediate radiosensitivity variants of ataxia-telangiectasia in the UK

    International Nuclear Information System (INIS)

    In a study of ataxia-telangiectasia (A-T) in the UK, patients in10 out of 60 families were shown to have a much lower level of chromosomal radiosensitivity compared with the majority of patients. In some patients the level of radiosensitivity was hardly distinguishable from normal. Patients in this group, however, could be distinguished clinically from the majority either by the later onset of severe cerebellar features or the slower rate of progress of the disorder. By using highly polymorphic microsatellite repeat markers a chromosome 11q22-23 haplotype common to the majority of these patients, and not occurring in any non-A-T chromosome in 60 families, was identified on one chromosome. The haplotype probably defines the region of the A-T gene in these families and the mutation associated with this haplotype may be much less severe than the second mutation thereby producing the slightly milder phenotype. (author)

  6. A haplotype common to intermediate radiosensitivity variants of ataxia-telangiectasia in the UK

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, A.M.R.; McConville, C.M.; Byrd, P.J. [Birmingham Univ. (United Kingdom). Medical School; Rotman, G.; Shiloh, Y. [Tel Aviv Univ. (Israel). Sackler School of Medicine

    1994-12-01

    In a study of ataxia-telangiectasia (A-T) in the UK, patients in10 out of 60 families were shown to have a much lower level of chromosomal radiosensitivity compared with the majority of patients. In some patients the level of radiosensitivity was hardly distinguishable from normal. Patients in this group, however, could be distinguished clinically from the majority either by the later onset of severe cerebellar features or the slower rate of progress of the disorder. By using highly polymorphic microsatellite repeat markers a chromosome 11q22-23 haplotype common to the majority of these patients, and not occurring in any non-A-T chromosome in 60 families, was identified on one chromosome. The haplotype probably defines the region of the A-T gene in these families and the mutation associated with this haplotype may be much less severe than the second mutation thereby producing the slightly milder phenotype. (author).

  7. Regulation of DNA repair in serum-stimulated xeroderma pigmentosum cells

    OpenAIRE

    1984-01-01

    The regulation of DNA repair during serum stimulation of quiescent cells was examined in normal human cells, in fibroblasts from three xeroderma pigmentosum complementation groups (A, C, and D), in xeroderma pigmentosum variant cells, and in ataxia telangiectasia cells. The regulation of nucleotide excision repair was examined by exposing cells to ultraviolet irradiation at discrete intervals after cell stimulation. Similarly, base excision repair was quantitated after exposure to methylmetha...

  8. Genetic, physical and functional analysis of the ataxia-telangiectasia locus on chromosome 11q22-23

    Energy Technology Data Exchange (ETDEWEB)

    Shiloh, Y.; Ziv, Y.; Savitski, K. [Tel Aviv Univ. (Israel)] [and others

    1994-09-01

    Ataxia-telangiectasia (A-T) is an autosomal recessive multisystem disorder featuring cerebellar degeneration, immunodeficiency, chromosomal instability, cancer susceptibility, and radiosensitivity. Four complementation groups have been observed in A-T. The two major groups, A and C, were localized to chromosome 11q22-23, and the other two, D and E, may map to the same chromosomal region. We developed an integrated system of positional and complementation cloning to identify the A-T gene(s). The A-T region was saturated with microsatellite markers by physically mapping markers generated at random by other labs and by identifying new polymorphic CA-repeats in YAC clones obtained from this region. According to recent linkage data based on these markers and linkage disequilibrium analysis in Moroccan Jewish A-T patients, the A-T(A) and A-T(C) mutations are contained within a 2 Mb interval between D11S1819 and D11S1960. This interval was cloned in YAC and cosmid contigs, and transcribed sequences were identified using the following methods: screening of cDNA libraries using cosmid clones; magnetic bead capture using YAC and cosmid clones; direct selection of cDNA clones using YAC clones immobilized on a solid matrix; and 3{prime} exon trapping. Preliminary results indicate that the A-T region is rich in transcribed sequences. Structural and functional analysis of these genes is being carried out by sequence analysis, by physical mapping using the cosmid contigs, and by testing their ability to complement the radiomimetic sensitivity of A-T cells.

  9. Imaging study of lymphoreticular tumor development in ataxia-telangiectasia and Nijmegen breakage syndrome

    International Nuclear Information System (INIS)

    Ataxia-telangiectasia (AT), or Louis-Bar syndrome, is an autosomal recessive illness characterized by progressive cerebellar ataxia, oculo-cutaneous telangiectasia, immunodeficiency combined with susceptibility to sinopulmonary infections and high incidence of neoplastic development. Nijmegen breakage syndrome (NBS) is a variant of AT, is also an autosomal recessive illness that presents cerebellar ataxia, as well as combined immunodeficiency and a tendency toward tumor development. Contrary to Louis-Bar syndrome, it doesn't present telangiectasia and exhibits a characteristics phenotype (short stature, bird-like face and microcephaly). Both entities are classified as syndrome of chromosomal instability or chromosomal fragility, a group which also includes Bloom syndrome and Fanconi anemia. All of these show an increase in the frequency of neoplastic pathologies, mainly lymphoid tumors. We present three patients,two with AT and one with NBS, who developed different lymphoma types in the course of the illness. We highlight the most outstanding aspects from a clinical-radiological point of view. (Author) 17 refs

  10. Sugammadex reversal of rocuronium-induced neuromuscular block in a patient with ataxia-telangiectasia

    International Nuclear Information System (INIS)

    A 17-year-old adolescent with ataxia-telangiectasia was scheduled to have laparoscopic colectomy for a resection of colon cancer. He had symptoms and signs of dyspnea, generalized dystonia, dysmetria, ataxia, and telangiectasia on the orbit. General anesthesia was performed, and rocuronium 30 mg was administered for muscle relaxation. Deep neuromuscular block (post-tetanic count: 0-8) was maintained for 95 minutes without additional rocuronium. On completion of surgery, sugammadex 80 mg was injected and train-of-four ratio was 0.93 at 210 seconds after administration. The tracheal tube was removed 5 min after the end of surgery. He recovered full spontaneous respiration and voluntary movements within 1 minute after extubation. After the surgery, he transferred to the intensive care unit and discharged 14 days after the surgery without any concrete problem. The reversal of rocuronium induced neuromuscular block by sugammadex was fast, complete, and recovered to the initial preoperative level of neuromuscular function in this patient. (author)

  11. Quantitative evaluation of brain involvement in ataxia telangiectasia by diffusion weighted MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Firat, Ahmet Kemal [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Radiology, Malatya 44280 (Turkey); Karakas, Hakki Muammer [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Radiology, Malatya 44280 (Turkey)]. E-mail: hkarakas@inonu.edu.tr; Firat, Yezdan [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Otorhinolaryngology, Malatya (Turkey); Yakinci, Cengiz [Inonu University Medical Faculty, Turgut Ozal Medical Center, Department of Pediatrics, Malatya (Turkey)

    2005-11-01

    Objective: To evaluate the value of diffusion weighted imaging (DWI) in diagnosing ataxia telangiectasia (AT) and to investigate the spatial distribution of cerebral microstructural changes caused by the disease. Methods: Six AT patients (9-13 years) and nine healthy control subjects were examined on 1.5 T scanner. In addition to conventional MR images, DWI were performed with a fat suppressed, multishot spin echo EPI sequence using B values of 0, 500 and 1000 s/mm{sup 2}. Mean ADC values were measured from 16 different supra and infratentorial location. The difference between controls and AT patients regarding ADC values, and the accuracy, sensitivity and specificity of them in discrimination were analyzed with t-tests, logistic regression analysis, ANOVA and ROC curves. Results: Conventional images of the controls were normal. In AT patients, the only conventional MR abnormality was cerebellar atrophy. The difference between both groups regarding mean ADC values was not significant for any of the cerebral structures. In contrary to cerebrum, cerebellar mean ADC values of patients and controls were statistically different (p < 0.011-0.0001). Patients and controls were classified with 100% accuracy using ADC values of cerebellar white matter and cortex together (p < 0.016). The cut-off ADC value (0.699 mm{sup 2}/s) for middle cerebellar cortex had produced highest (100%) sensitivity and specificity. There was a difference between superior, middle and inferior cerebellar cortex regarding ADC values (p < 0.026). Superior cerebellar cortex (0.987 {+-} 0.1956 mm{sup 2}/s) had higher ADC values than the middle and inferior cerebellar cortex. Conclusion: DWI provides a supplementary and objective imaging finding in AT. This finding is highly accurate in the radiological discrimination of healthy subjects and AT. Our findings also implicate that AT causes a diffuse atrophy and mostly affects superior part of the cortex.

  12. Health risks for ataxia-telangiectasia mutated heterozygotes: a systematic review, meta-analysis and evidence-based guideline.

    Science.gov (United States)

    van Os, N J H; Roeleveld, N; Weemaes, C M R; Jongmans, M C J; Janssens, G O; Taylor, A M R; Hoogerbrugge, N; Willemsen, M A A P

    2016-08-01

    Ataxia-telangiectasia (AT) is an autosomal recessive neurodegenerative disorder with immunodeficiency and an increased risk of developing cancer, caused by mutations in the ataxia-telangiectasia mutated (ATM) gene. Logically, blood relatives may also carry a pathogenic ATM mutation. Female carriers of such a mutation have an increased risk of breast cancer. Other health risks for carriers are suspected but have never been studied systematically. Consequently, evidence-based guidelines for carriers are not available yet. We systematically analyzed all literature and found that ATM mutation carriers have a reduced life expectancy because of mortality from cancer and ischemic heart diseases (RR 1.7, 95% CI 1.2-2.4) and an increased risk of developing cancer (RR 1.5, 95% CI 0.9-2.4), in particular breast cancer (RRwomen 3.0, 95% CI 2.1-4.5), and cancers of the digestive tract. Associations between ATM heterozygosity and other health risks have been suggested, but clear evidence is lacking. Based on these results, we propose that all female carriers of 40-50 years of age and female ATM c.7271T>G mutation carriers from 25 years of age onwards be offered intensified surveillance programs for breast cancer. Furthermore, all carriers should be made aware of lifestyle factors that contribute to the development of cardiovascular diseases and diabetes. PMID:26662178

  13. Ataxia-telangiectasia-mutated (ATM) and NBS1-dependent phosphorylation of Chk1 on Ser-317 in response to ionizing radiation

    DEFF Research Database (Denmark)

    Gatei, Magtouf; Sloper, Katie; Sørensen, Claus Storgaard;

    2003-01-01

    In mammals, the ATM (ataxia-telangiectasia-mutated) and ATR (ATM and Rad3-related) protein kinases function as critical regulators of the cellular DNA damage response. The checkpoint functions of ATR and ATM are mediated, in part, by a pair of checkpoint effector kinases termed Chk1 and Chk2. In...

  14. Enhanced chromatid damage in blood lymphocytes after G2 phase x irradiation, a marker of the ataxia-telangiectasia gene

    International Nuclear Information System (INIS)

    An assay for ataxia-telangiectasia (A-T) heterozygotes, i.e., healthy carriers of the A-T gene(s), requiring only a small sample (3.5 mL) of peripheral blood, is described. Frequencies of chromatid aberrations in phytohemagglutinin-stimulated blood lymphocytes collected by demecolcine from 0.5 hour to 1.5 hours after x irradiation with 58 roentgens were twofold to threefold higher in A-T heterozygotes than in clinically normal controls and twofold to three-fold higher in A-T patients (homozygotes) than in A-T gene carriers. The persistence of chromatid breaks and gaps in lymphocytes following radiation-induced DNA damage during G2 suggests a deficiency or deficiencies in DNA repair that may be the defect at the molecular level that results in the enhanced radiosensitivity and cancer proneness characterizing A-T gene carriers and patients

  15. Discovery of Novel 3-Quinoline Carboxamides as Potent, Selective, and Orally Bioavailable Inhibitors of Ataxia Telangiectasia Mutated (ATM) Kinase.

    Science.gov (United States)

    Degorce, Sébastien L; Barlaam, Bernard; Cadogan, Elaine; Dishington, Allan; Ducray, Richard; Glossop, Steven C; Hassall, Lorraine A; Lach, Franck; Lau, Alan; McGuire, Thomas M; Nowak, Thorsten; Ouvry, Gilles; Pike, Kurt G; Thomason, Andrew G

    2016-07-14

    A novel series of 3-quinoline carboxamides has been discovered and optimized as selective inhibitors of the ataxia telangiectasia mutated (ATM) kinase. From a modestly potent HTS hit (4), we identified molecules such as 6-[6-(methoxymethyl)-3-pyridinyl]-4-{[(1R)-1-(tetrahydro-2H-pyran-4-yl)ethyl]amino}-3-quinolinecarboxamide (72) and 7-fluoro-6-[6-(methoxymethyl)pyridin-3-yl]-4-{[(1S)-1-(1-methyl-1H-pyrazol-3-yl)ethyl]amino}quinoline-3-carboxamide (74) as potent and highly selective ATM inhibitors with overall ADME properties suitable for oral administration. 72 and 74 constitute excellent oral tools to probe ATM inhibition in vivo. Efficacy in combination with the DSB-inducing agent irinotecan was observed in a disease relevant model. PMID:27259031

  16. A YAC contig spanning the ataxia-telangiectasia locus (groups A and C) at 11q22-q23

    Energy Technology Data Exchange (ETDEWEB)

    Rotman, G.; Savitsky, K.; Ziv, Y. [Tel Aviv Univ. Ramat Aviv (Israel)] [and others

    1994-11-15

    Ataxia-telangiectasia (A-T) is an autosomal recessive disease involving cerebellar degeneration, immunodeficiency, cancer predisposition, chromosomal instability and radiosensitivity. A-T is heterogeneous, and the majority of A-T cases are associated with two complementation groups, A and C. The ATA and ATC loci are closely linked at chromosome 11q22-q23. Recombination mapping and linkage disequilibrium analysis have confined both loci between the markers D11S1817 and D11S927. Construction of this contig was expedited by prior generation of a region-specific ICRF sublibrary using Alu-PCR products derived from a radiation hybrid. The contig was expanded further by screening the libraries with Alu-PCR products derived from YAC clones and with STSs from YAC ends. YAC clones were aligned by fingerprinting with moderately repetitive probes. 56 refs., 5 figs., 1 tab.

  17. Effects of radiation therapy for Hodgkin's disease in a child with ataxia telangiectasia: a clinical, biological and pathologic study

    International Nuclear Information System (INIS)

    Stage I lymphocyte-predominant Hodgkin's disease was diagnosed in a 44-month-old girl. Although immune deficiency was suspected and IgA deficiency demonstrated, the diagnosis of an ataxia-telangiectasia (AT)-like syndrome was not confirmed until eight weeks later when results of studies on the radiosensitivity of cultured skin fibroblasts were available. The child had none of the usual physical stigmata of AT. Severe acute radiation damage followed the treatment of this child with standard doses of radiation therapy. Clinical, pathologic, and radiobiologic correlations are drawn. The diagnosis of a malignant lymphoma disorder in children under the age of five should alert clinicians to the possibility of immune deficiency and, even in the absence of classical physical signs, to AT in particular. Suggestions for the management of future similar cases are put forward

  18. Imaging study of lymphoreticular tumor development in ataxia-telangiectasia and Nijmegen breakage syndrome; Estudio por imagen del desarrollo de tumores linforreticulares en la ataxia telangiectasia y el sindrome de Nijmegen

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Leon, M. I.; Ceres-Ruiz, L.; Cuesta, M. A.; Garcia-Martin, F. J. [Hospital Materno-Infantil C.H.U. Carlos Haya. Malaga (Spain)

    2003-07-01

    Ataxia-telangiectasia (AT), or Louis-Bar syndrome, is an autosomal recessive illness characterized by progressive cerebellar ataxia, oculo-cutaneous telangiectasia, immunodeficiency combined with susceptibility to sinopulmonary infections and high incidence of neoplastic development. Nijmegen breakage syndrome (NBS) is a variant of AT, is also an autosomal recessive illness that presents cerebellar ataxia, as well as combined immunodeficiency and a tendency toward tumor development. Contrary to Louis-Bar syndrome, it doesn't present telangiectasia and exhibits a characteristics phenotype (short stature, bird-like face and microcephaly). Both entities are classified as syndrome of chromosomal instability or chromosomal fragility, a group which also includes Bloom syndrome and Fanconi anemia. All of these show an increase in the frequency of neoplastic pathologies, mainly lymphoid tumors. We present three patients,two with AT and one with NBS, who developed different lymphoma types in the course of the illness. We highlight the most outstanding aspects from a clinical-radiological point of view. (Author) 17 refs.

  19. Construction of a transcription map around the gene for ataxia telangiectasia: Identification of at least four novel genes

    Energy Technology Data Exchange (ETDEWEB)

    Stankovic, T.; Byrd, P.J.; Cooper, P.R. [Univ. of Birmingham (United Kingdom)] [and others

    1997-03-01

    We have constructed YAC, PAC, and cosmid contigs in the ataxia-telangiectasia gene region and used the assembled clones to isolate expressed sequences by exon trapping and hybridization selection. In the interval between D11S1819 and D11S2029, exons and cDNAs for potentially 13 different genes were identified. Three of these genes, F37, K28, and 6.82, are large novel genes expressed in a variety of different tissues. K28 shows sequence homology to the Rab GTP binding protein family and gene 6.82 homology to the rabbit vasopressin activated calcium mobilizing receptor, while gene F37 has no homology to any known sequence in the database. Three further clones, exon 6.41 and cDNAs K22 and E74, from the interval between D11S1819 and D11S2029, appear to be expressed endogenous retrovirus sequences. The fourth large novel gene, E14, together with two further possible novel genes, E13 and E3, was identified from exons and cDNAs in the more telomeric 300-kb interval between markers D11S2029 and D11S2179. These are in addition to the genes for mitochondrial acetoacetyl-CoA-acetyltransferase (ACAT) and the ATM gene in the same region. Genes E3, E13, and E14 do not show homology to any known genes. K28, 6.82, ACAT, and ATM all appear to have the same transcriptional orientation toward the telomere. 39 refs., 3 figs., 1 tab.

  20. Fibroblasts from ataxia telangiectasia (AT) and AT heterozygotes show an enhanced level of residual DNA double-strand breaks after low dose-rate γ-irradiation as assayed by pulsed field gel electrophoresis

    International Nuclear Information System (INIS)

    Skin fibroblasts from ataxia telangiectasia (AT) patients, obligate AT heterozygotes (ATH) and normal individuals were studied for colony-forming ability and repair of DNA double-strand breaks (dsb) after γ-irradiation. AT cells were three to four times more radiosensitive than normal cells at high and low dose-rate exposures; ATH cells, however, showed a marginally increased radiosensitivity after high dose-rate γ-irradiation and an intermediate response after low dose-rate exposure. The repair of DNA dsb was studied by pulsed field gel electrophoresis. After high dose-rate γ-irradiation the repair time constant (t1/2) was around 1h for normal, ATH and AT cells. After low dose-rate γ-irradiation the fraction of residual dsb was 1.4% for normal, 2.1% for ATH and 5.2% for AT cells, demonstrating a deficiency in the repair of a small fraction of dsb in AT. (author)

  1. Medical Management of Pediatric Malignant Bowel Obstruction in a Patient with Burkitt's Lymphoma and Ataxia Telangiectasia Using Continuous Ambulatory Drug Delivery System.

    Science.gov (United States)

    Ghoshal, Arunangshu; Salins, Naveen; Damani, Anuja; Deodhar, Jayita; Muckaden, M A

    2016-01-01

    Malignant bowel obstruction (MBO) is commonly seen in patients with advanced abdominal cancers. The incidence of pediatric MBO in a patient with Burkitt's lymphoma and ataxia telangiectasia is rare, with no published case reports till now. Conservative management of inoperable MBO results in relief of symptoms and improves quality of life. An 11-year-old boy with Burkitt's lymphoma and ataxia telangiectasia was referred to pediatric palliative care with MBO. The objective of this report is to demonstrate conservative management of pediatric MBO using continuous ambulatory drug delivery system. The patient was initiated on continuous ambulatory drug delivery (CADD) system for symptom relief. MBO was reversed with conservative management and the child was discharged on self-collapsible portable elastomeric continuous infusion pump under the supervision of a local family physician. The child remained comfortable at home for 4 weeks until his death. His parents were satisfied with the child's symptom control, quality of life, and were able to care for the child at home. In a resource-limited setting, managing patients at home using elastomeric continuous infusion pumps instead of expensive automated CADD is a practical pharmacoeconomic approach. PMID:26862790

  2. Inhibition of Ataxia Telangiectasia Mutated (ATM) Kinase Suppresses Herpes Simplex Virus Type 1 (HSV-1) Keratitis

    OpenAIRE

    Alekseev, Oleg; Donovan, Kelly; Azizkhan-Clifford, Jane

    2014-01-01

    This study shows that inhibition of ATM, an apical kinase in the mammalian DNA damage response pathway, suppresses HSV-1 replication in corneal epithelial cells and explanted human and rabbit corneas. ATM inhibition also reduces stromal keratitis severity in mice without causing corneal toxicity.

  3. Acceptor proteins for poly(ADP-ribose) in irradiated normal human and ataxia telangiectasia (AT) fibroblasts

    International Nuclear Information System (INIS)

    Poly(ADP-ribose) polymerase activity is stimulated by DNA strand breaks and may participate in DNA repair. Since treatment of cells with DNA damaging agents stimulated the poly(ADP-ribosylation) of a specific set of proteins, the authors have analyzed the acceptors in irradiated human fibroblasts from normal individuals and from patients with AT, a disease associated with a hypersensitivity to ionizing radiation. Cells were permeabilized and incubated with /sup 32/P-NAD, proteins were separated by polyacrylamide gel electrophoresis, and the poly (ADP-ribose) acceptors were detected by autoradiography. In all four strains, the major acceptor was the 116 kd auto-modified polymerase, while other prominent radioactive bands were at 2, 45, and 60 kd. Labeling of these bands was increased following irradiation of the cells with 3-30 Gy. Of interest was the detection of a poly (ADP-ribosylated) protein at 19 kd in the two normal strains but not in either AT strain. The results suggest that a defect in the ADP-ribosylation of the 19 kd protein is associated with AT and possible with the hypersensitivity of AT cells to ionizing radiation

  4. Spontaneous and induced chromosome breakage in chorionic villus samples: a cytogenetic approach to first trimester prenatal diagnosis of ataxia telangiectasia syndrome.

    Science.gov (United States)

    Llerena, J; Murer-Orlando, M; McGuire, M; Zahed, L; Sheridan, R J; Berry, A C; Bobrow, M

    1989-01-01

    Patients with ataxia telangiectasia (AT) syndrome exhibit a high level of spontaneous chromosome aberrations, with hypersensitivity to gamma radiation and radiomimetic chemicals at the chromosomal and cellular level. Previously pregnancies at risk for AT have been screened solely by analysis of amniotic fluid samples. In this report we describe a cytogenetic approach to the prenatal diagnosis of AT using chorionic villus sampling (CVS). Levels of spontaneous and induced (gamma radiation and bleomycin) chromosome breakage were established in direct, semidirect, and culture preparations of CVS samples from normal pregnancies. The methods developed were then successfully applied to the screening of a pregnancy at risk for AT. Semidirect preparations showed normal levels of chromosome breakage, and this result was further confirmed in chorion, amniotic fluid, and lymphocyte cultures. In chorion villus samples, gamma radiation is probably the easiest and most reliable way of discriminating between unaffected fetuses and those with AT. PMID:2468772

  5. Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway

    Energy Technology Data Exchange (ETDEWEB)

    Nagane, Masaki; Yasui, Hironobu; Sakai, Yuri; Yamamori, Tohru [Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818 (Japan); Niwa, Koichi [Laboratory of Biochemistry, Department of Food and Cosmetic Science, Faculty of Bioindustry, Tokyo University of Agriculture, Abashiri 099-2493 (Japan); Hattori, Yuichi [Department of Molecular and Medical Pharmacology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan); Kondo, Takashi [Department of Radiological Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194 (Japan); Inanami, Osamu, E-mail: inanami@vetmed.hokudai.ac.jp [Laboratory of Radiation Biology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818 (Japan)

    2015-01-02

    Highlights: • eNOS activity is increased in BAECs exposed to X-rays. • ATM is involved in this increased eNOS activity. • HSP90 modulates the radiation-induced activation of ATM and eNOS. - Abstract: In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced by treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90.

  6. Activation of eNOS in endothelial cells exposed to ionizing radiation involves components of the DNA damage response pathway

    International Nuclear Information System (INIS)

    Highlights: • eNOS activity is increased in BAECs exposed to X-rays. • ATM is involved in this increased eNOS activity. • HSP90 modulates the radiation-induced activation of ATM and eNOS. - Abstract: In this study, the involvement of ataxia telangiectasia mutated (ATM) kinase and heat shock protein 90 (HSP90) in endothelial nitric oxide synthase (eNOS) activation was investigated in X-irradiated bovine aortic endothelial cells. The activity of nitric oxide synthase (NOS) and the phosphorylation of serine 1179 of eNOS (eNOS-Ser1179) were significantly increased in irradiated cells. The radiation-induced increases in NOS activity and eNOS-Ser1179 phosphorylation levels were significantly reduced by treatment with either an ATM inhibitor (Ku-60019) or an HSP90 inhibitor (geldanamycin). Geldanamycin was furthermore found to suppress the radiation-induced phosphorylation of ATM-Ser1181. Our results indicate that the radiation-induced eNOS activation in bovine aortic endothelial cells is regulated by ATM and HSP90

  7. No evidence for association of ataxia-telangiectasia mutated gene T2119C and C3161G amino acid substitution variants with risk of breast cancer

    International Nuclear Information System (INIS)

    There is evidence that certain mutations in the double-strand break repair pathway ataxia-telangiectasia mutated gene act in a dominant-negative manner to increase the risk of breast cancer. There are also some reports to suggest that the amino acid substitution variants T2119C Ser707Pro and C3161G Pro1054Arg may be associated with breast cancer risk. We investigate the breast cancer risk associated with these two nonconservative amino acid substitution variants using a large Australian population-based case–control study. The polymorphisms were genotyped in more than 1300 cases and 600 controls using 5' exonuclease assays. Case–control analyses and genotype distributions were compared by logistic regression. The 2119C variant was rare, occurring at frequencies of 1.4 and 1.3% in cases and controls, respectively (P = 0.8). There was no difference in genotype distribution between cases and controls (P = 0.8), and the TC genotype was not associated with increased risk of breast cancer (adjusted odds ratio = 1.08, 95% confidence interval = 0.59–1.97, P = 0.8). Similarly, the 3161G variant was no more common in cases than in controls (2.9% versus 2.2%, P = 0.2), there was no difference in genotype distribution between cases and controls (P = 0.1), and the CG genotype was not associated with an increased risk of breast cancer (adjusted odds ratio = 1.30, 95% confidence interval = 0.85–1.98, P = 0.2). This lack of evidence for an association persisted within groups defined by the family history of breast cancer or by age. The 2119C and 3161G amino acid substitution variants are not associated with moderate or high risks of breast cancer in Australian women

  8. Loss of ataxia-telangiectasia-mutated protein expression correlates with poor prognosis but benefits from anthracycline-containing adjuvant chemotherapy in breast cancer.

    Science.gov (United States)

    Suh, Koung Jin; Ryu, Han Suk; Lee, Kyung-Hun; Kim, Hyojin; Min, Ahrum; Kim, Tae-Yong; Yang, Yaewon; Moon, Hyeong-Gon; Han, Sae-Won; Oh, Do-Youn; Han, Wonshik; Park, In Ae; Noh, Dong-Young; Im, Seock-Ah

    2016-07-01

    We investigated the correlation of ataxia-telangiectasia-mutated (ATM) protein expression with clinicopathological features and prognosis in patients with breast cancer. ATM expression was determined by immunohistochemistry in 420 surgically resected breast tumors. ATM loss was observed in 126/407 evaluable cases (31.0 %), and was significantly associated with larger tumor size, lymph node metastasis, higher tumor grade, and ER- and/or PR-negative status. ATM loss was also associated with significantly lower disease-free survival rates than those in patients with intact ATM (5-year disease-free survival rate 81.2 vs. 90.7 %, p = 0.015). In multivariate analysis, ATM loss combined with abnormal p53 expression was an independent predictor of shorter disease-free survival [hazard ratio (HR) 3.48; 95 % confidence interval (CI), 1.48-8.17, p = 0.004]. A tendency towards a poorer prognosis was observed for tumoral ATM loss alone, although statistical significance was not reached (HR 1.74; 95 % CI 0.95-3.20; p = 0.075). In subgroup analysis, ATM loss was associated with shorter disease-free survival in patients who did not receive adjuvant anthracycline chemotherapy (5-year disease-free survival rate 92.7 % in intact ATM group vs. 68.1 % in ATM loss group, p = 0.002), but this poor prognosis was overcome in patients who did (5-year disease-free survival rate 89.8 vs. 84.4 %, p = 0.243), suggesting more benefit from anthracycline-based chemotherapy. Tumors with loss of ATM expression have a poor prognosis and their prognoses are dependent on the use of adjuvant anthracycline. ATM loss might be a practical tool for predicting benefits from anthracycline-based adjuvant therapy. PMID:27329169

  9. Chromosomal Aberrations in Normal and AT Cells Exposed to High Dose of Low Dose Rate Irradiation

    Science.gov (United States)

    Kawata, T.; Shigematsu, N.; Kawaguchi, O.; Liu, C.; Furusawa, Y.; Hirayama, R.; George, K.; Cucinotta, F.

    2011-01-01

    Ataxia telangiectasia (A-T) is a human autosomally recessive syndrome characterized by cerebellar ataxia, telangiectases, immune dysfunction, and genomic instability, and high rate of cancer incidence. A-T cell lines are abnormally sensitive to agents that induce DNA double strand breaks, including ionizing radiation. The diverse clinical features in individuals affected by A-T and the complex cellular phenotypes are all linked to the functional inactivation of a single gene (AT mutated). It is well known that cells deficient in ATM show increased yields of both simple and complex chromosomal aberrations after high-dose-rate irradiation, but, less is known on how cells respond to low-dose-rate irradiation. It has been shown that AT cells contain a large number of unrejoined breaks after both low-dose-rate irradiation and high-dose-rate irradiation, however sensitivity for chromosomal aberrations at low-dose-rate are less often studied. To study how AT cells respond to low-dose-rate irradiation, we exposed confluent normal and AT fibroblast cells to up to 3 Gy of gamma-irradiation at a dose rate of 0.5 Gy/day and analyzed chromosomal aberrations in G0 using fusion PCC (Premature Chromosomal Condensation) technique. Giemsa staining showed that 1 Gy induces around 0.36 unrejoined fragments per cell in normal cells and around 1.35 fragments in AT cells, whereas 3Gy induces around 0.65 fragments in normal cells and around 3.3 fragments in AT cells. This result indicates that AT cells can rejoin breaks less effectively in G0 phase of the cell cycle? compared to normal cells. We also analyzed chromosomal exchanges in normal and AT cells after exposure to 3 Gy of low-dose-rate rays using a combination of G0 PCC and FISH techniques. Misrejoining was detected in the AT cells only? When cells irradiated with 3 Gy were subcultured and G2 chromosomal aberrations were analyzed using calyculin-A induced PCC technique, the yield of unrejoined breaks decreased in both normal and AT

  10. Ataxia telangiectasia-mutated-Rad3-related DNA damage checkpoint signaling pathway triggered by hepatitis B virus infection

    Institute of Scientific and Technical Information of China (English)

    Fan Zhao; Qing-Jun Ma; Hui Zhong; Ning-Bo Hou; Xiao-Li Yang; Xiang He; Yu Liu; Yan-Hong Zhang; Cong-Wen Wei; Ting Song; Li Li

    2008-01-01

    AIM: To explore whether acute cellular DNA damage response is induced upon hepatitis B virus (HBV) infection and the effects of the HBV infection. METHODS: We incubated HL7702 hepatocytes with HBV-positive serum, mimicking a natural HBV infection process. We used immunoblotting to evaluate protein expression levels in HBV-infected cells or in non-infected cells; immunofluorescence to show ATR foci ands Chk1 phosphorylation loci formation; flow cytometry to analyze the cell cycle and apoptosis; ultraviolet (UV) radiation and ionizing radiation (IR)-treated cells to mimic DNA damage; and Trypan blue staining to count the viable cells.RESULTS: We found that HBV infection induced an increased steady state of ATR protein and increased phosphorylation of multiple downstream targets including Chkl, p53 and H2AX. In contrast to ATR and its target, the phosphorylated form of ATM at Ser-1981 and its downstream substrate Chk2 phosphorylation at Thr-68 did not visibly increase upon infection. However, the level of Mre11 and p21 were reduced beginning at 0.5 h after HBV-positive serum addition. Also, HBV infection led to transient cell cycle arrest in the S and the G2 phases without accompanying increased apoptosis. Research on cell survival changes upon radiation following HBV infection showed that survival of UV-treated host cells was greatly increased by HBV infection, owing to the reduced apoptosis. Meanwhile, survival of IR-treated host cells was reduced by HBV infection. CONCLUSION: HBV infection activates ATR DNA damage response to replication stress and abrogates the checkpoint signaling controlled by DNA damage response.

  11. Molecular studies on the nature of the repair defect in ataxia-telangiectasia and their implications for cellular radiobiology

    International Nuclear Information System (INIS)

    We have utilized DNA transfer and recombinant DNA techniques to probe DNA double-strand break repair in the human ionizing radiation-sensitive genetic syndrome ataxia-telangiectasis (A-T). Using restriction enzyme-generated double-strand breaks in the coding sequence of a selectable gene we have detected a significantly greater frequency of mis-repair of such breaks in a permanent A-T cell line compared with cell lines of normal radiosensitivity. This mis-repair in A-T can explain many of the clinical features of the disease but was insufficiently detailed to address the broad problem of DNA repair mechanisms relevant to ionizing radiation-induced damage. To extend these observations of DNA double-strand break mis-repair we have now applied this type of repair assay to novel, de novo induced mammalian X-ray-sensitive cell lines and to appropriate Escherichia coli mutants. In both cellular systems we have found some equivalence to the A-T repair defect. Studies on one E. coli mutant suggest an involvement of a topoisomerase activity in DNA double-strand break mis-repair, which may be relevant to the biochemical defect in A-T. (author)

  12. What Is Ataxia-Telangiectasia?

    Science.gov (United States)

    ... hallmark of A-T: "telangiectasia," or tiny red "spider" veins which appear in the corners of the ... 1,000 times more frequently than the general population. Lymphoma and leukemia are particularly common types of ...

  13. ATM dependent low-dose hyper-radiosensitivity in mutation induced by heavy ions in mammalian cells

    International Nuclear Information System (INIS)

    On the basis of our last year's work that proved the existence of Low dose Hyper-radiosensitivity (HRS) and later appeared radioresistance (termed Induced radioresistance (IRR)) in normal human skin fibroblast cells exposed to carbon ions irradiation with the endpoints of survival and mutation, we further study the role of ataxia telangiectasia mutated (ATM) kinase, which has been indicated to work in the mechanism of HRS/IRR by low linear energy transfer (LET) irradiation. Normal human fibroblast cells were pretreated with stimulator for ATM kinase, chloroquine, or with ATM inhibitor, KU55933 prior to carbon irradiation, survival fraction and HPRT mutation frequency were measured to test the existence of HRS/IRR. Interestingly there was no HRS/IRR in either ATM stimulator or inhibitor pretreatment. The western blot suggest a dose-dependent increase of ATM kinase activity, which further confirm the role of ATM in the mechanism of HRS/IRR. (author)

  14. Regulation of ATM in DNA double strand break repair accounts for the radiosensitivity in human cells exposed to high linear energy transfer ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Xue Lian, E-mail: xuelian@suda.edu.cn [School of Radiation Medicine and Public Health, Medical College of Soochow University, No. 199, Ren' ai Road, Suzhou 215123 (China); Yu Dong, E-mail: ydong@ncc.go.jp [Tumor Endocrinology Project, National Cancer Center Research Institute, 5-1-1 Tsukiji, Chuo-ku, Tokyo 104-0045 (Japan); Furusawa, Yoshiya; Okayasu, Ryuichi [Heavy-Ion Radiobiology Research Group, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba-shi 263-8555 (Japan); Tong Jian; Cao Jianping; Fan Saijun [School of Radiation Medicine and Public Health, Medical College of Soochow University, No. 199, Ren' ai Road, Suzhou 215123 (China)

    2009-11-02

    High linear energy transfer (LET) radiation shows different biological effects from low-LET radiation. The complex nature of high LET radiation-induced damage, especially the clustered DNA damage, brings about slow repair of DNA double strand breaks (DSBs), which finally lead to higher lethality and chromosome aberration. Ionizing radiation (IR) induced DNA DSBs are repaired by both non-homologous end-joining (NHEJ) and homologous recombination repair (HRR) pathways in mammalian cells. The novel function of ataxia telangiectasia-mutated (ATM) protein is its involvement in the DSB repair of slow kinetics for 'dirty' breaks rejoining by NHEJ, this suggests that ATM may play a more important role in high LET radiation-induced DNA damage. We show here that KU55933, an ATM inhibitor could distinctly lower the clonogenic survival in normal human skin fibroblast cells exposed to carbon ion radiation and dramatically impair the normal process for DSB repair. We also implicated the involvement of ATM in the two pathways of DNA DSB repair, with DNA-PKcs and Rad51 as the representative proteins. The phosphorylation of DNA-PKcs at Thr-2609 with both immunoblotting and immunofluorescent staining indicated an ATM-dependent change, while for Rad51, KU55933 pretreatment could postpone the formation of nuclear Rad51 foci. Interestingly, we also found that pretreatment with chloroquine, an ATM stimulator could protect cells from carbon ion radiation only at lower doses. For doses over 1 Gy, protection was no longer observed. There was a dose-dependent increase for ATM kinase activity, with saturation at about 1 Gy. Chloroquine pretreatment prior to 1 Gy of carbon ion radiation did not enhance the autophosphorylation of ATM at serine 1981. The function of ATM in G2/M checkpoint arrest facilitated DSB repair in high-LET irradiation. Our results provide a possible mechanism for the direct involvement of ATM in DSB repair by high-LET irradiation.

  15. Targeting Werner syndrome protein sensitizes U-2 OS osteosarcoma cells to selenium-induced DNA damage response and necrotic death

    DEFF Research Database (Denmark)

    Cheng, Wen-Hsing; Wu, Ryan T Y; Wu, Min;

    2012-01-01

    to MSeA-induced necrotic death. Co-treatment with the ataxia-telangiectasia mutated (ATM) kinase inhibitor KU55933 desensitized the control shRNA cells, but not WRN shRNA cells, to MSeA treatment. WRN did not affect MSeA-induced ATM phosphorylation on Ser-1981 or H2A.X phosphorylation on Ser-139, but...

  16. Adaptive Response to ionizing Radiation Induced by Low Doses of Gamma Rays in Human Lymphoblastoid Cell Lines

    International Nuclear Information System (INIS)

    When cells are exposed to low doses of a mutagenic or clastogenic agents, they often become less sensitive to the effects of a higher does administered subsequently. Such adaptive responses were first described in Escherichia coli and mammalian cells to low doses of an alkylating agent. Since most of the studies have been carried out with human lymphocytes, it is urgently necessary to study this effect in different cellular systems. Its relation with inherent cellular radiosensitivity and underlying mechanism also remain to be answered. In this study, adaptive response by 1 cGy of gamma rays was investigated in three human lymphoblastoid cell lines which were derived from ataxia telangiectasia homozygote, ataxia telangiectasia heterozygote, and normal individual. Experiments were carried out by delivering 1 cGy followed by 50 cGy of gamma radiation and chromatid breaks were scored as an endpoint. The results indicate that prior exposure to 1 cGy of gamma rays reduces the number of chromatid breaks induced by subsequent higher does (50 cGy). The expression of this adaptive response was similar among three cell lines despite of their different radiosensitivity. When 3-aminobenzamide, an inhibitor of poly (ADP-ribose) polymerase, was added after 50 cGy, adaptive responses were abolished in all the tested cell lines. Therefore it is suggested that the adaptive response can be observed in human lymphoblastoid cell lines. Which was first documented through this study. The expression of adaptive response was similar among the cell lines regardless of their radiosensitivity. The elimination of the adaptive response by 3-aminobenzamide is consistent with the proposal that this adaptive response is the result of the induction of a certain chromosomal repair mechanism

  17. Methods for detection of ataxia telangiectasia mutations

    Science.gov (United States)

    Gatti, Richard A.

    2005-10-04

    The present invention is directed to a method of screening large, complex, polyexonic eukaryotic genes such as the ATM gene for mutations and polymorphisms by an improved version of single strand conformation polymorphism (SSCP) electrophoresis that allows electrophoresis of two or three amplified segments in a single lane. The present invention also is directed to new mutations and polymorphisms in the ATM gene that are useful in performing more accurate screening of human DNA samples for mutations and in distinguishing mutations from polymorphisms, thereby improving the efficiency of automated screening methods.

  18. Ataxia-Telangiectasia (A-T)

    Science.gov (United States)

    ... on a single mutated copy of the ATM gene, their child will be affected. Mutations are changes in the DNA from the normal, healthy copy. The most common types of ATM mutations are: splicing (35%), nonsense (25%), and frameshift (25%). Each of ...

  19. Multiple Defects of Cell Cycle Checkpoints in U937-ASPI3K, an U937 Cell Mutant Stably Expressing Anti-Sense ATM Gene cDNA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    (Ataxia-telangiectasia mutated gene (ATM) functions in control of cell cycle checkpoints in responding to DNA damage and protects cells from undergoing apoptosis. Knock-out within tumor cells of endogenous ATM will achieve therapeutic benefits and nable a better understanding of the decisive mechanisms of cell death or survival in response to DNA damaging agents. ) In present paper, we sought to characterize the cell cycle checkpoint profiles in U937-ASPI3K, a U937 cell mutant that was previously established with endogenous ATM knock-out phenotype. Synchronized U937-ASPI3K was exposed to 137Cs irradiation, G1, S, G2/M cell cycle checkpoint profiles were evaluated by determining cell cycle kinetics, p53/p21 protein, cyclin dependent kinase 2 (CDK2) and p34CDC2 kinase activity in response to irradiation. U937-ASPI3K exhibited multiple defects in cell cycle checkpoints as defined by failing to arrest cells upon irradiation. The accumulation of cellular p53/p21 protein and inhibition of CDK kinase was also abolished in U937-ASPI3K. It was concluded that the stable expression of anti-sense PI3K cDNA fragment completely abolished multiple cell cycle checkpoints in U937-ASPI3K, and hence U937-ASPI3K with an AT-like phenotype could serves as a valuable model system for investigating the signal transduction pathway in responding to DNA damaging-based cancer therapy.

  20. Methacryloxylethyl Cetyl Ammonium Chloride Induces DNA Damage and Apoptosis in Human Dental Pulp Cells via Generation of Oxidative Stress.

    Science.gov (United States)

    Jiao, Yang; Ma, Sai; Wang, Yirong; Li, Jing; Shan, Lequn; Sun, Jinlong; Chen, Jihua

    2016-01-01

    The polymerizable antibacterial monomer methacryloxylethyl cetyl ammonium chloride (DMAE-CB) has provided an effective strategy to combat dental caries. However, the application of such material raises the question about the biological safety and the question remains open. The mechanism of this toxic action, however, is not yet clearly understood. The present study aims at providing novel insight into the possible causal link between cellular oxidative stress and DNA damage, as well as apoptosis in human dental pulp cells exposed to DMAE-CB. The enhanced formation of reactive oxygen species and depletion of glutathione, as well as differential changes in activities of superoxide dismutase, glutathione peroxidase, and catalase in DMAE-CB-treated cells indicated oxidative stress. By using substances that can alter GSH synthesis, we found that GSH was the key component in the regulation of cell response towards oxidative stress induced by DMAE-CB. The increase in oxidative stress-sensitive 8-Oxo-2'-deoxyguanosine (8-OHdG) content, formation of γ-H2AX and cell cycle G1 phase arrest indicated that DNA damage occurred as a result of the interaction between DNA base and ROS beyond the capacities of antioxidant mechanisms in cells exposed to DMAE-CB. Such oxidative DNA damage thus triggers the activation of ataxia telangiectasia-mutated (ATM) signaling, the intrinsic apoptotic pathway, and destruction of mitochondrial morphology and function. PMID:27143955

  1. Methacryloxylethyl Cetyl Ammonium Chloride Induces DNA Damage and Apoptosis in Human Dental Pulp Cells via Generation of Oxidative Stress

    Science.gov (United States)

    Jiao, Yang; Ma, Sai; Wang, Yirong; Li, Jing; Shan, Lequn; Sun, Jinlong; Chen, Jihua

    2016-01-01

    The polymerizable antibacterial monomer methacryloxylethyl cetyl ammonium chloride (DMAE-CB) has provided an effective strategy to combat dental caries. However, the application of such material raises the question about the biological safety and the question remains open. The mechanism of this toxic action, however, is not yet clearly understood. The present study aims at providing novel insight into the possible causal link between cellular oxidative stress and DNA damage, as well as apoptosis in human dental pulp cells exposed to DMAE-CB. The enhanced formation of reactive oxygen species and depletion of glutathione, as well as differential changes in activities of superoxide dismutase, glutathione peroxidase, and catalase in DMAE-CB-treated cells indicated oxidative stress. By using substances that can alter GSH synthesis, we found that GSH was the key component in the regulation of cell response towards oxidative stress induced by DMAE-CB. The increase in oxidative stress-sensitive 8-Oxo-2'-deoxyguanosine (8-OHdG) content, formation of γ-H2AX and cell cycle G1 phase arrest indicated that DNA damage occurred as a result of the interaction between DNA base and ROS beyond the capacities of antioxidant mechanisms in cells exposed to DMAE-CB. Such oxidative DNA damage thus triggers the activation of ataxia telangiectasia-mutated (ATM) signaling, the intrinsic apoptotic pathway, and destruction of mitochondrial morphology and function.

  2. Distinctive features of single nucleotide alterations in induced pluripotent stem cells with different types of DNA repair deficiency disorders.

    Science.gov (United States)

    Okamura, Kohji; Sakaguchi, Hironari; Sakamoto-Abutani, Rie; Nakanishi, Mahito; Nishimura, Ken; Yamazaki-Inoue, Mayu; Ohtaka, Manami; Periasamy, Vaiyapuri Subbarayan; Alshatwi, Ali Abdullah; Higuchi, Akon; Hanaoka, Kazunori; Nakabayashi, Kazuhiko; Takada, Shuji; Hata, Kenichiro; Toyoda, Masashi; Umezawa, Akihiro

    2016-01-01

    Disease-specific induced pluripotent stem cells (iPSCs) have been used as a model to analyze pathogenesis of disease. In this study, we generated iPSCs derived from a fibroblastic cell line of xeroderma pigmentosum (XP) group A (XPA-iPSCs), a rare autosomal recessive hereditary disease in which patients develop skin cancer in the areas of skin exposed to sunlight. XPA-iPSCs exhibited hypersensitivity to ultraviolet exposure and accumulation of single-nucleotide substitutions when compared with ataxia telangiectasia-derived iPSCs that were established in a previous study. However, XPA-iPSCs did not show any chromosomal instability in vitro, i.e. intact chromosomes were maintained. The results were mutually compensating for examining two major sources of mutations, nucleotide excision repair deficiency and double-strand break repair deficiency. Like XP patients, XPA-iPSCs accumulated single-nucleotide substitutions that are associated with malignant melanoma, a manifestation of XP. These results indicate that XPA-iPSCs may serve a monitoring tool (analogous to the Ames test but using mammalian cells) to measure single-nucleotide alterations, and may be a good model to clarify pathogenesis of XP. In addition, XPA-iPSCs may allow us to facilitate development of drugs that delay genetic alteration and decrease hypersensitivity to ultraviolet for therapeutic applications. PMID:27197874

  3. Distinctive features of single nucleotide alterations in induced pluripotent stem cells with different types of DNA repair deficiency disorders

    Science.gov (United States)

    Okamura, Kohji; Sakaguchi, Hironari; Sakamoto-Abutani, Rie; Nakanishi, Mahito; Nishimura, Ken; Yamazaki-Inoue, Mayu; Ohtaka, Manami; Periasamy, Vaiyapuri Subbarayan; Alshatwi, Ali Abdullah; Higuchi, Akon; Hanaoka, Kazunori; Nakabayashi, Kazuhiko; Takada, Shuji; Hata, Kenichiro; Toyoda, Masashi; Umezawa, Akihiro

    2016-01-01

    Disease-specific induced pluripotent stem cells (iPSCs) have been used as a model to analyze pathogenesis of disease. In this study, we generated iPSCs derived from a fibroblastic cell line of xeroderma pigmentosum (XP) group A (XPA-iPSCs), a rare autosomal recessive hereditary disease in which patients develop skin cancer in the areas of skin exposed to sunlight. XPA-iPSCs exhibited hypersensitivity to ultraviolet exposure and accumulation of single-nucleotide substitutions when compared with ataxia telangiectasia-derived iPSCs that were established in a previous study. However, XPA-iPSCs did not show any chromosomal instability in vitro, i.e. intact chromosomes were maintained. The results were mutually compensating for examining two major sources of mutations, nucleotide excision repair deficiency and double-strand break repair deficiency. Like XP patients, XPA-iPSCs accumulated single-nucleotide substitutions that are associated with malignant melanoma, a manifestation of XP. These results indicate that XPA-iPSCs may serve a monitoring tool (analogous to the Ames test but using mammalian cells) to measure single-nucleotide alterations, and may be a good model to clarify pathogenesis of XP. In addition, XPA-iPSCs may allow us to facilitate development of drugs that delay genetic alteration and decrease hypersensitivity to ultraviolet for therapeutic applications. PMID:27197874

  4. DNA fork displacement rates in human cells

    International Nuclear Information System (INIS)

    DNA fork displacement rates were measured in 20 human cell lines by a bromodeoxyuridine-313 nm photolysis technique. Cell lines included representatives of normal diploid, Fanconi's anemia, ataxia telangiectasia, xeroderma pigmentosum, trisomy-21 and several transformed lines. The average value for all the cell lines was 0.53 +- 0.08 μm/min. The average value for individual cell lines, however, displayed a 30% variation. Less than 10% of variation in the fork displacement rate appears to be due to the experimental technique; the remainder is probably due to true variation among the cell types and to culture conditions. (Auth.)

  5. Breast cancer stem cell-like cells are more sensitive to ionizing radiation than non-stem cells: role of ATM.

    Directory of Open Access Journals (Sweden)

    Seog-Young Kim

    Full Text Available There are contradictory observations about the different radiosensitivities of cancer stem cells and cancer non-stem cells. To resolve these contradictory observations, we studied radiosensitivities by employing breast cancer stem cell (CSC-like MDA-MB231 and MDA-MB453 cells as well as their corresponding non-stem cells. CSC-like cells proliferate without differentiating and have characteristics of tumor-initiating cells [1]. These cells were exposed to γ-rays (1.25-8.75 Gy and survival curves were determined by colony formation. A final slope, D(0, of the survival curve for each cell line was determined to measure radiosensitivity. The D(0 of CSC-like and non-stem MDA-MB-453 cells were 1.16 Gy and 1.55 Gy, respectively. Similar results were observed in MDA-MB-231 cells (0.94 Gy vs. 1.56 Gy. After determination of radiosensitivity, we investigated intrinsic cellular determinants which influence radiosensitivity including cell cycle distribution, free-radical scavengers and DNA repair. We observed that even though cell cycle status and antioxidant content may contribute to differential radiosensitivity, differential DNA repair capacity may be a greater determinant of radiosensitivity. Unlike non-stem cells, CSC-like cells have little/no sublethal damage repair, a low intracellular level of ataxia telangiectasia mutated (ATM and delay of γ-H2AX foci removal (DNA strand break repair. These results suggest that low DNA repair capacity is responsible for the high radiosensitivity of these CSC-like cells.

  6. Alterations in radioresistance of eucaryotic cells after the transfer of genomic wildtype DNA and metallothionein genes

    International Nuclear Information System (INIS)

    The presented paper describes experiments concerning the alteration of radiosensitivity of eucaryotic cells after gene transfer. Ionizing radiation (γ- or X-ray) induces DNA single- or double strand breaks, which are religated by an unknown repair system. Repair deficient cells are highly sensitive to ionizing radiation. In the experiments described, cells from a patient with the heritable disease Ataxia telangiectasia were used as well as two X-ray sensitive CHO mutant cell lines. After gene transfer of an intact human DNA repair gene or a metallothionein gene the cells should regain radioresistance. (orig.)

  7. MicroRNA-22 promotes cell survival upon UV radiation by repressing PTEN

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Guangyun [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States); Jilin Province Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun (China); Shi, Yuling [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States); Wu, Zhao-Hui, E-mail: zwu6@uthsc.edu [Department of Pathology and Laboratory Medicine, University of Tennessee Health Science Center, Memphis, TN (United States); Center for Adult Cancer Research, University of Tennessee Health Science Center, Memphis, TN (United States)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer miR-22 is induced in cells treated with UV radiation. Black-Right-Pointing-Pointer ATM is required for miR-22 induction in response to UV. Black-Right-Pointing-Pointer miR-22 targets 3 Prime -UTR of PTEN to repress its expression in UV-treated cells. Black-Right-Pointing-Pointer Upregulated miR-22 inhibits apoptosis in cells exposed to UV. -- Abstract: DNA damage response upon UV radiation involves a complex network of cellular events required for maintaining the homeostasis and restoring genomic stability of the cells. As a new class of players involved in DNA damage response, the regulation and function of microRNAs in response to UV remain poorly understood. Here we show that UV radiation induces a significant increase of miR-22 expression, which appears to be dependent on the activation of DNA damage responding kinase ATM (ataxia telangiectasia mutated). Increased miR-22 expression may result from enhanced miR-22 maturation in cells exposed to UV. We further found that tumor suppressor gene phosphatase and tensin homolog (PTEN) expression was inversely correlated with miR-22 induction and UV-induced PTEN repression was attenuated by overexpression of a miR-22 inhibitor. Moreover, increased miR-22 expression significantly inhibited the activation of caspase signaling cascade, leading to enhanced cell survival upon UV radiation. Collectively, these results indicate that miR-22 is an important player in the cellular stress response upon UV radiation, which may promote cell survival via the repression of PTEN expression.

  8. The use of recombinant DNA plasmids for the determination of DNA-repair and recombination in cultured mammalian cells.

    OpenAIRE

    Cox, R.; Masson, W. K.; Debenham, P G; Webb, M. B.

    1984-01-01

    Using the recombinant plasmid pSV2gpt and DNA transfer techniques, cell mediated DNA ligation and recombination of plasmid DNA have been demonstrated in four human cell lines. Data suggesting the involvement of a possible defect in the cellular equilibrium between ligation and exonuclease digestion of double strand DNA scissions in an ataxia-telangiectasia (A-T) cell line is discussed. The same A-T line was grossly proficient in DNA recombination but it will be necessary to distinguish betwee...

  9. DNA damaging and cell cycle effects of the topoisomerase I poison camptothecin in irradiated human cells

    International Nuclear Information System (INIS)

    This study addressed the potential radiosensitizing and DNA-damaging actions of the DNA topoisomerase I poison camptothecin (CPT) on SV40 transformed normal (MRC5CVI) and ataxia-telangiectasia (AT5BIVA) fibroblast cell lines. In both cell lines CPT induced a dose-dependent delay of cells in S phase, followed by a dose-dependent trapping in G2/M phase. Acute X-irradiation produced patterns of G2/M arrest and S-phase delay similar to those observed for CPT in the MRC5CVI cell line, but no S phase delay was observed in the AT5BIVA cell line consistent with the ataxia-telangiectasia phenotype of this cell line. X-irradiation of CPT-treated cells resulted in additive prolongation of S phase delay in MRC5CVI cultures and additive effects for cell killing in both cell lines. The potential for topoisomerase I-DNA cross-linking by CPT was not altered by 24 h pretreatment with CPT, or by acute X-irradiation. Hypersensitivity of AT5BIVA to CPT was not attributable to elevated levels of complex trapping. (author)

  10. Selective cytotoxicity of benzyl isothiocyanate in the proliferating fibroblastoid cells.

    Science.gov (United States)

    Miyoshi, Noriyuki; Uchida, Koji; Osawa, Toshihiko; Nakamura, Yoshimasa

    2007-02-01

    In the present study, experiments using presynchronization culture cells demonstrated that benzyl ITC (BITC), previously isolated from a tropical papaya fruit extract, induced the cytotoxic effect preferentially in the proliferating human colon CCD-18Co cells to the quiescent ones. Quiescent CCD-18Co cells were virtually unaffected by BITC and marginal cytotoxicity was observed at 15 microM. We observed that BITC dramatically induced the p53 phosphorylation and stabilization only in the quiescent (G(0)/G(1) phase-arrested) cells, but not significantly in the proliferating human colon CCD-18Co cells when compared with quiescent ones. We also observed ataxia telangiectasia-mutated (ATM) phosphorylation in the quiescent cells. The BITC-induced p53 phosphorylation was counteracted by caffeine treatment, implying the involvement of an ATM/ataxia telangiectasia and Rad3-related kinase signaling pathway. Moreover, downregulation of p53 by a siRNA resulted in the enhancement of susceptibility to undergo apoptosis by BITC. We also showed here that depletion of p53 abrogated G(0)/G(1) arrest accompanied by the declined expression of p21(waf1/cip1) and p27(kip1) in CCD-18Co cells. In conclusion, we identified p53 as a potential negative regulator of the apoptosis induction by BITC in the normal colon CCD-18Co cells through the inhibition of cell-cycle progression at the G(0)/G(1) phase. PMID:17096346

  11. Gene for ataxia-telangiectasia complementation group D (ATDC)

    Science.gov (United States)

    Murnane, John P.; Painter, Robert B.; Kapp, Leon N.; Yu, Loh-Chung

    1995-03-07

    Disclosed herein is a new gene, an AT gene for complementation group D, the ATDC gene and fragments thereof. Nucleic acid probes for said gene are provided as well as proteins encoded by said gene, cDNA therefrom, preferably a 3 kilobase (kb) cDNA, and recombinant nucleic acid molecules for expression of said proteins. Further disclosed are methods to detect mutations in said gene, preferably methods employing the polymerase chain reaction (PCR). Also disclosed are methods to detect AT genes from other AT complementation groups.

  12. Cell death by the quinoxaline dioxide DCQ in human colon cancer cells is enhanced under hypoxia and is independent of p53 and p21

    International Nuclear Information System (INIS)

    We have shown that the radio sensitizer DCQ enhances sensitivity of HCT116 human colon cancer cells to hypoxia. However, it is not known whether the p53 or p21 genes influence cellular response to DCQ. In this study, we used HCT116 that are either wildtype for p53 and p21, null for p53 or null for p21 to understand the role of these genes in DCQ toxicity. HCT116 cells were exposed to DCQ and incubated under normoxia or hypoxia and the viability, colony forming ability, DNA damage and apoptotic responses of these cells was determined, in addition to the modulation of HIF-1α and of p53, p21, caspase-2, and of the ataxia telangiectasia mutated (ATM) target PIDD-C. DCQ decreased colony forming ability and viability of all HCT116 cells to a greater extent under hypoxia than normoxia and the p21-/-cell line was most sensitive. Cells had different HIF-1α responses to hypoxia and/or drug treatment. In p53+/+, DCQ significantly inhibited the hypoxia-induced increases in HIF-1α protein, in contrast to the absence of a significant HIF-1α increase or modulation by DCQ in p21-/- cells. In p53-/- cells, 10 μM DCQ significantly reduced HIF-1α expression, especially under hypoxia, despite the constitutive expression of this protein in control cells. Higher DCQ doses induced PreG1-phase increase and apoptosis, however, lower doses caused mitotic catastrophe. In p53+/+ cells, apoptosis correlated with the increased expression of the pro-apoptotic caspase-2 and inhibition of the pro-survival protein PIDD-C. Exposure of p53+/+ cells to DCQ induced single strand breaks and triggered the activation of the nuclear kinase ATM by phosphorylation at Ser-1981 in all cell cycle phases. On the other hand, no drug toxicity to normal FHs74 Int human intestinal cell line was observed. Collectively, our findings indicate that DCQ reduces the colony survival of HCT116 and induces apoptosis even in cells that are null for p53 or p21, which makes it a molecule of clinical significance, since

  13. miR-30a can inhibit DNA replication by targeting RPA1 thus slowing cancer cell proliferation.

    Science.gov (United States)

    Zou, Zhenyou; Ni, Mengjie; Zhang, Jing; Chen, Yongfeng; Ma, Hongyu; Qian, Shihan; Tang, Longhua; Tang, Jiamei; Yao, Hailun; Zhao, Chengbin; Lu, Xiongwen; Sun, Hongyang; Qian, Jue; Mao, Xiaoting; Lu, Xulin; Liu, Qun; Zen, Juping; Wu, Hanbing; Bao, Zhaosheng; Lin, Shudan; Sheng, Hongyu; Li, Yunlong; Liang, Yong; Chen, Zhiqiang; Zong, Dan

    2016-07-15

    Cell proliferation was inhibited following forced over-expression of miR-30a in the ovary cancer cell line A2780DX5 and the gastric cancer cell line SGC7901R. Interestingly, miR-30a targets the DNA replication protein RPA1, hinders the replication of DNA and induces DNA fragmentation. Furthermore, ataxia telangiectasia mutated (ATM) and checkpoint kinase 2 (CHK2) were phosphorylated after DNA damage, which induced p53 expression, thus triggering the S-phase checkpoint, arresting cell cycle progression and ultimately initiating cancer cell apoptosis. Therefore, forced miR-30a over-expression in cancer cells can be a potential way to inhibit tumour development. PMID:27208176

  14. Biological behaviour of buccal cells exposed to blue light

    International Nuclear Information System (INIS)

    Blue light is used in dental practise to cure resin-based materials, but the path of the light often includes oral tissues such as gingival tissues. While adverse effects of blue light exposure on cells - such as retina cells - are well known, few studies have investigated the impact of blue light exposure on oral cells. The aim of the present in vitro study was to assess the biological effects of blue light emitted by two dental curing devices (a plasma-arc and a light-emitting diode curing unit) on human gingival fibroblasts. Light intensities and light-induced temperature rise were respectively measured with a radiometer and a thermocouple. Cellular response to blue light exposure was assessed by the observation of cell morphology (scanning electron microscopy) and the estimation of cell mitochondrial activity (MTT assay). Light intensities measured at the clinical distance were 488 ± 42 mW/cm2 for the plasma-arc unit and ranged from 61 ± 5 to 140 ± 16 mW/cm2 for the light-emitting diodes unit, according to the curing program used. The highest temperature rise was 0.5 and 3.5 deg. C for exposure to the plasma-arc light and to the light-emitting diodes light, respectively. Results showed no differences between exposed- and non-exposed cells in regards to cell morphology. However, cells exposed to blue light presented an increased mitochondrial activity compared to control cells (non-exposed), and mostly those exposed to plasma-arc light

  15. The rejoining of x-ray-induced breaks in human interphase chromosomes from normal and ataxia cells

    International Nuclear Information System (INIS)

    Patients with the genetically inherited recessive disease ataxia telangiectasia (AT), in addition to various clinical disorders including cancer proneness, are extremely sensitive to the lethal effects of ionizing radiations. Following irradiation, cells cultured from such individuals show greatly enhanced cell killing, and marked increase in the production of chromosomal aberrations. Consequently, it has been proposed that AT cells are deficient in the repair of radiation-induced damage to DNA, yet it has not been possible to demonstrate the nature of this deficiency at the molecular level. The authors have measured the rejoining rates of x-ray-induced breakage in the interphase chromosomes of normal human, and AT fibroblasts by means of premature chromosome condensation (PCC). Results show that neither the level of initially sustained x-ray damage, nor the rate at which PCC fragments rejoin, are significantly different between the two cell types. However, an appreciably larger fraction of breaks failed to rejoin in ataxia cells

  16. Atmospheric-pressure plasma-jet from micronozzle array and its biological effects on living cells for cancer therapy

    Science.gov (United States)

    Kim, Kangil; Choi, Jae Duk; Hong, Yong Cheol; Kim, Geunyoung; Noh, Eun Joo; Lee, Jong-Soo; Yang, Sang Sik

    2011-02-01

    We propose a plasma-jet device with a micrometer-sized nozzle array for use in a cancer therapy. Also, we show the biological effects of atmospheric-pressure plasma on living cells. Nitrogen-plasma activated a surrogate DNA damage signal transduction pathway, called the ataxia telangiectasia mutated (ATM)-checkpoint kinase 2 pathway, suggesting that the nitrogen-plasma generates DNA double-strand breaks. Phosphorylation of H2AX and p53 was detected in the plasma-treated cells, leading to apoptotic cell death. Thus, an effect for the nitrogen plasma in the control of apoptotic cell death provides insight into the how biological effects of the nitrogen-plasma can be applied to the control of cell survival, a finding with potential therapeutic implications.

  17. Interferon-β-armed oncolytic adenovirus induces both apoptosis and necroptosis in cancer cells

    Institute of Scientific and Technical Information of China (English)

    Hongling Huang; Tian Xiao; Lingfeng He; Hongbin Ji; Xin-Yuan Liu

    2012-01-01

    Interferon-β (IFN-β) has been widely used in cancer therapy,but the clinical trial results are generally disappointing.Our previous studies have shown that an oncolytic adenovirus carrying IFN-β (ZD55-IFN-β) exhibits significant anti-tumor activities.However,the underlying mechanisms are not clear.Here we showed that ZD55-IFN-β infection-induced S-phase cell cycle arrest in a p53-dependent manner by activating the ataxia telangiectasia mutated-dependent DNA damage pathway.In addition, ZD55-IFN-β infection could initiate both caspase-dependent apoptosis and necroptosis in cancer cells.More importantly,ZD55-IFN-β showed a synergistic effect on cancer cells when combined with doxorubicin.These results suggest that the combination of ZD55-IFN-β with doxorubicin may represent a promising clinical strategy in cancer therapy.

  18. Normal inhibition of DNA synthesis following γ-irradiation of radiosensitive cell lines from patients with Down's syndrome and Alzheimer's disease

    International Nuclear Information System (INIS)

    Inhibition of DNA synthesis was studied in γ-iradiated lymphoblastoid cells from patients with Alzheimer's disease and Down's syndrome. A normal biphasic pattern of inhibition was observed over a dose range of 0-4 krad of γ-rays in all of the cell lines 3 out of 4 Down's and all the Alzheimer's cell lines were shown to be hypersensitive to ionizing radiation based on induced chromosomal aberrations. Increased G2 phase delay, comparable to that occurring in ataxia-telangiectasia cells, was observed for some of the cell lines, after exposure to γ-rays. Contrary to other data in the literature these results demonstrate that radioresistand DNA synthesis is not an intrinsic feature of all disorders characterized by radiosensitivitey. (author).; 25 refs.; 2 figs.; 1 tab

  19. Mammalian cells exposed to ionizing radiation: Structural and biochemical aspects.

    Science.gov (United States)

    Sabanero, Myrna; Azorín-Vega, Juan Carlos; Flores-Villavicencio, Lérida Liss; Castruita-Dominguez, J Pedro; Vallejo, Miguel Angel; Barbosa-Sabanero, Gloria; Cordova-Fraga, Teodoro; Sosa-Aquino, Modesto

    2016-02-01

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv/year) and subsequently exposure to high doses produces greater effects in people. It has been reported that people who have been exposed to low doses of radiation (less than 50 mSv/year) and subsequently are exposed to high doses, have greater effects. However, at a molecular and biochemical level, it is an unknown alteration. This study, analyzes the susceptibility of a biological system (HeLa ATCC CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/90 s). Our research considers multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin microfilaments), nuclei (DAPI), and genomic DNA. The results indicate, that cells exposed to ionizing radiation show structural alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin microfilaments. Similar alterations were observed in cells treated with a genotoxic agent (200 μM H2O2/1h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between various line cells. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. PMID:26656429

  20. Administration of ON 01210.Na after exposure to ionizing radiation protects bone marrow cells by attenuating DNA damage response

    International Nuclear Information System (INIS)

    Ionizing radiation-induced hematopoietic injury could occur either due to accidental exposure or due to diagnostic and therapeutic interventions. Currently there is no approved drug to mitigate radiation toxicity in hematopoietic cells. This study investigates the potential of ON 01210.Na, a chlorobenzylsulfone derivative, in ameliorating radiation-induced hematopoietic toxicity when administered after exposure to radiation. We also investigate the molecular mechanisms underlying this activity. Male C3H/HeN mice (n = 5 mice per group; 6-8 weeks old) were exposed to a sub-lethal dose (5 Gy) of γ radiation using a 137Cs source at a dose rate of 0.77 Gy/min. Two doses of ON 01210.Na (500 mg/kg body weight) were administered subcutaneously at 24 h and 36 h after radiation exposure. Mitigation of hematopoietic toxicity by ON 01210.Na was investigated by peripheral white blood cell (WBC) and platelet counts at 3, 7, 21, and 28 d after radiation exposure. Granulocyte macrophage colony forming unit (GM-CFU) assay was done using isolated bone marrow cells, and terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) was performed on bone marrow sections at 7 d post-exposure. The DNA damage response pathway involving ataxia telangiectasia mutated (ATM) and p53 was investigated by Western blot in bone marrow cells at 7 d post-exposure. Compared to the vehicle, ON 01210.Na treated mice showed accelerated recovery of peripheral WBC and platelet counts. Post-irradiation treatment of mice with ON 01210.Na also resulted in higher GM-CFU counts. The mitigation effects were accompanied by attenuation of ATM-p53-dependent DNA damage response in the bone marrow cells of ON 01210.Na treated mice. Both phospho-ATM and phospho-p53 were significantly lower in the bone marrow cells of ON 01210.Na treated than in vehicle treated mice. Furthermore, the Bcl2:Bax ratio was higher in the drug treated mice than the vehicle treated groups. ON 01210.Na treatment significantly

  1. DNA damage and repair in human cells exposed to sunlight

    International Nuclear Information System (INIS)

    Cultured human cells were treated with direct sunlight under conditions which minimised the hypertonic, hyperthermic and fixative effects of solar radiation. Sunlight produced similar levels of DNA strand breaks as equitoxic 254 nm UV in two fibroblast strains and a melanoma cell line, but DNA repair synthesis and inhibition of semiconservative DNA synthesis and of DNA chain elongation were significantly less for sunlight-exposed cells. DNA breaks induced by sunlight were removed more rapidly. Thus, the repair of solar damage differs considerably from 254 nm UV repair. Glass-filtered sunlight (>320 nm) was not toxic to cells and did not induce repair synthesis but gave a low level of short-lived DNA breaks and some inhibition of DNA chain elongation; thymidine uptake was enhanced. Filtered sunlight slightly enhanced UV-induced repair synthesis and UV toxicity; photoreactivation of UV damage was not found. Attempts to transform human fibroblasts using sunlight, with or without phorbol ester, were unsuccessful. (author)

  2. Synthesis of protein in intestinal cells exposed to cholera toxin

    International Nuclear Information System (INIS)

    The mechanism by which cyclic adenosine monophosphate (AMP), formed by intestinal epithelial cells in response to cholera toxin, ultimately results in alterations in water and electrolyte transport is poorly understood. Several studies have indicated that inhibitors of transcription or translation block much of the transport of ions and water in the intestine and edema formation in tissue elicited by cholera toxin. Data presented in this study confirmed the inhibitory effects of cycloheximide on cholera toxin-induced fluid accumulation in the rabbit intestinal loop model. Neither cycloheximide nor actinomycin D altered the amount of cyclic AMP that accumulated in intestinal cells and Chinese hamster ovary cells exposed to cholera toxin. An increase in [3H] leucine incorporation was readily demonstrable in intestinal epithelial cells from rabbits challenged with Vibrio cholerae. Similarly, intestinal epithelial cells incubated with cholera toxin for 4 hr synthesized substantially more protein than controls as determined by relative incorporation of [35S] methionine. Most of the new protein synthesized in response to cholera toxin was membrane associated and of high molecular weight. The possible significance of the toxin-induced protein relative to cholera pathogenesis was discussed

  3. Mammalian cells exposed to ionizing radiation: structural and biochemical aspects

    International Nuclear Information System (INIS)

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv / year) and subsequently exposure to high doses have greater effects in people. However, it is unknown molecular and biochemical level alteration. This study, analyzes the susceptibility of a biological system (HeLa Atcc CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/ 90). Our evaluate multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin micro filaments), nuclei (D API), genomic DNA. The results indicate, that cells exposed to ionizing radiation structurally show alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin micro filaments. Similar alterations were observed in cells treated with a genotoxic agent (200μM H2O2/1 h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. (Author)

  4. Mammalian cells exposed to ionizing radiation: structural and biochemical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Sabanero, M.; Flores V, L. L. [Universidad de Guanajuato, Departamento de Biologia, DCNE, Noria Alta s/n, 36250 Guanajuato, Gto. (Mexico); Azorin V, J. C.; Vallejo, M. A.; Cordova F, T.; Sosa A, M. [Universidad de Guanajuato, Departamento de Ingenieria Fisica, DCI, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Castruita D, J. P. [Universidad de Guadalajara, Departamento de Ecologia, CUCBA, Las Agujas, 45100 Zapopan, Jalisco (Mexico); Barbosa S, G., E-mail: myrna.sabanero@gmail.com [Universidad de Guanajuato, Departamento de Ciencias Medicas, DCS, 20 de Enero No. 929, Col. Obregon, 37000 Leon, Guanajuato (Mexico)

    2015-10-15

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv / year) and subsequently exposure to high doses have greater effects in people. However, it is unknown molecular and biochemical level alteration. This study, analyzes the susceptibility of a biological system (HeLa Atcc CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/ 90). Our evaluate multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin micro filaments), nuclei (D API), genomic DNA. The results indicate, that cells exposed to ionizing radiation structurally show alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin micro filaments. Similar alterations were observed in cells treated with a genotoxic agent (200μM H{sub 2}O{sub 2}/1 h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. (Author)

  5. Biological effectiveness of mammalian cells exposed to heavy ion beams

    International Nuclear Information System (INIS)

    The LET-relative biological effectiveness (RBE) spectra were investigated using cultured V79 cells by accelerated heavy ions. Cells were exposed to ''3He-, ''1''2C-, and ''2''0Ne-ion beams at HIMAC, the Medical Cyclotron at NIRS, and RRC at RIKEN with an LET ranging over approximately 10-500 keV/μm under aerobic conditions. Cell-survival curves were fitted by equations from the linear-quadratic model to obtain survival parameters, and the RBE values were analyzed as a function of LET. The RBE increased with LET, reaching a maximum at around 200 keV/μm, then decreased with a further increase in LET. Clear splits of the LET-RBE spectrum were found among ion-spices. The LET-RBE spectra were fitted by a newly contrived equation that including three parameters: LP, A, and W. The parameters will indicate a LET that gives a maximum RBE, a related value to maximum RBE, and indicates the width of the peak of RBE, respectively. It is also found that the parameters can be defined as functions of atomic numbers of the accelerated ions. At a given LET, the RBE-value for lighter ions was higher than that for heavier ions at lower-LET region. The LET that gives maximum RBE shifts to higher LET for heavier-ions, and the maximum values of the peak of RBE decreased with the atomic number of the irradiated ions. (author)

  6. Survival and viability of cells from iron depositing bacterial strains in pretests for the EXPOSE-R2-Experiment

    OpenAIRE

    Feyh, N.; de Vera, J.P.; Szewzyk, U

    2014-01-01

    Five environmental isolates (Pseudomonas sp. BS1, Hyphomonas sp. BS2, Tetrasphaera sp. FL1, Pedomicrobium sp. FL6 and Leptothrix sp. OT_B_406) were chosen for EXPOSE-R2 including pretests (EVT1/2, SVT) due to their ability to form Fe(III)-oxyhydroxide-containing biofilms as observed for natural communities of iron depositing bacteria. Samples were produced by drying iron-containing cell aggregates on Mars regolith simulant mixtures (S-/P-MRS) (Böttger et al., 2012). Different Mars- and ...

  7. Modification of cell volume and proliferative capacity of Pseudokirchneriella subcapitata cells exposed to metal stress

    International Nuclear Information System (INIS)

    Highlights: •Metals induce morphological alterations on P. subcapitata. •Algal cell cycle consists: mother cell growth; cell division, with two nucleus divisions; release of four autospores. •Cu(II) and Cr(VI) arrest cell growth before the first nuclear division. •Cd(II) arrests cell growth after the second nuclear division but before the cytokinesis. •The approach used can be useful in the elucidation of different modes of action of pollutants. -- Abstract: The impact of metals (Cd, Cr, Cu and Zn) on growth, cell volume and cell division of the freshwater alga Pseudokirchneriella subcapitata exposed over a period of 72 h was investigated. The algal cells were exposed to three nominal concentrations of each metal: low (closed to 72 h-EC10 values), intermediate (closed to 72 h-EC50 values) and high (upper than 72 h-EC90 values). The exposure to low metal concentrations resulted in a decrease of cell volume. On the contrary, for the highest metal concentrations an increase of cell volume was observed; this effect was particularly notorious for Cd and less pronounced for Zn. Two behaviours were found when algal cells were exposed to intermediate concentrations of metals: Cu(II) and Cr(VI) induced a reduction of cell volume, while Cd(II) and Zn(II) provoked an opposite effect. The simultaneous nucleus staining and cell image analysis, allowed distinguishing three phases in P. subcapitata cell cycle: growth of mother cell; cell division, which includes two divisions of the nucleus; and, release of four autospores. The exposure of P. subcapitata cells to the highest metal concentrations resulted in the arrest of cell growth before the first nucleus division [for Cr(VI) and Cu(II)] or after the second nucleus division but before the cytokinesis (release of autospores) when exposed to Cd(II). The different impact of metals on algal cell volume and cell-cycle progression, suggests that different toxicity mechanisms underlie the action of different metals studied

  8. Modification of cell volume and proliferative capacity of Pseudokirchneriella subcapitata cells exposed to metal stress

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Manuela D. [Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Soares, Eduardo V., E-mail: evs@isep.ipp.pt [Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2014-02-15

    Highlights: •Metals induce morphological alterations on P. subcapitata. •Algal cell cycle consists: mother cell growth; cell division, with two nucleus divisions; release of four autospores. •Cu(II) and Cr(VI) arrest cell growth before the first nuclear division. •Cd(II) arrests cell growth after the second nuclear division but before the cytokinesis. •The approach used can be useful in the elucidation of different modes of action of pollutants. -- Abstract: The impact of metals (Cd, Cr, Cu and Zn) on growth, cell volume and cell division of the freshwater alga Pseudokirchneriella subcapitata exposed over a period of 72 h was investigated. The algal cells were exposed to three nominal concentrations of each metal: low (closed to 72 h-EC{sub 10} values), intermediate (closed to 72 h-EC{sub 50} values) and high (upper than 72 h-EC{sub 90} values). The exposure to low metal concentrations resulted in a decrease of cell volume. On the contrary, for the highest metal concentrations an increase of cell volume was observed; this effect was particularly notorious for Cd and less pronounced for Zn. Two behaviours were found when algal cells were exposed to intermediate concentrations of metals: Cu(II) and Cr(VI) induced a reduction of cell volume, while Cd(II) and Zn(II) provoked an opposite effect. The simultaneous nucleus staining and cell image analysis, allowed distinguishing three phases in P. subcapitata cell cycle: growth of mother cell; cell division, which includes two divisions of the nucleus; and, release of four autospores. The exposure of P. subcapitata cells to the highest metal concentrations resulted in the arrest of cell growth before the first nucleus division [for Cr(VI) and Cu(II)] or after the second nucleus division but before the cytokinesis (release of autospores) when exposed to Cd(II). The different impact of metals on algal cell volume and cell-cycle progression, suggests that different toxicity mechanisms underlie the action of

  9. Cell growth, intracellular calcium concentration and metabolic cooperation measured in cells exposed to 50 Hz electromagnetic fields

    International Nuclear Information System (INIS)

    Colony-forming efficiency, DNA/protein and DNA/cell were measured in cells exposed to magnetic fields of 0.2 and 1 mT at a frequency of 50 Hz. Intracellular calcium concentrations were measured in cells exposed to 0.3 and 1 mT at 50 Hz. Metabolic cooperation was measured in cells exposed to 1 mT at 50 Hz. No significant effects of the fields were observed. 20 refs., 10 figs

  10. Potassium ion influx measurements on cultured Chinese hamster cells exposed to 60-hertz electromagnetic fields

    International Nuclear Information System (INIS)

    Potassium ion influx was measured by monitoring 42KCl uptake by Chinese hamster ovary (CHO) cells grown in suspension culture and exposed in the culture medium to 60-Hz electromagnetic fields up to 2.85 V/m. In the presence of the field CHO cells exhibited two components of uptake, the same as previously observed for those grown under normal conditions; both these components of influx were decreased when compared to sham-exposed cells. Although decreases were consistently observed in exposed cells when plotted as loge of uptake, the differences between the means of the calculated fluxes of exposed and sham-exposed cells were quite small (on the order of 4-7%). When standard deviations were calculated, there was no significant difference between these means; however, when time-paired uptake data were analyzed, the differences were found to be statistically significant. Cells exposed only to the magnetic field exhibited similar small decreases in influx rates when compared to sham-exposed cells, suggesting that the reduction in K+ uptake could be attributed to the magnetic field. Additionally, intracellular K+ levels were measured over a prolonged exposure period (96 h), and no apparent differences in intracellular K+ levels were observed between field-exposed and sham-exposed cultures. These results indicate that high-strength electric fields have a small effect on the rate of transport of potassium ions but no effect on long-term maintenance of intracellular K+

  11. Ataksi-Telenjiektazi: İki Kardeş Olgunun Sunumu

    OpenAIRE

    Çatal, Ferhat; Aslan, Mahmut; Topal, Erdem; Ermiştekin, Halime; Sinanoğlu, M. Selçuk

    2014-01-01

    Characterized by progressive cerebellar ataxia, cutaneous and conjuctival telangiectasia, ocular apraxy, immunodeficiency, and increased risk of malignancy, ataxia-telangiectasia is a rare neurodegenerative disorder that shows signs of autosomal recessive transmission. The ataxia-telangiectasia gene is located in chromosome 11q22-23. Various degrees of abnormalities in T and B cell immunities have also been described. It is known that the incidence of both T cell and B cell leukemia and lymph...

  12. Mutagenesis in repair-deficient human cell strains

    International Nuclear Information System (INIS)

    Cell killing and mutation experiments with a range of human skin fibroblast cell strains are described. With ultraviolet light increased sensitivity to cell killing was observed in excision-defective xeroderma pigmentosum cell strains and cells from Cockayne syndrome patients and patient 11961 from no known syndrome with no observable defects in repair. Xeroderma pigmentosum variant cells with defects in daughter strand repair did not show enhanced sensitivity. All of these cell strains were hypermutable when compared with normal cells and this allows the authors to propose that (i) excision repair may, as in bacteria, be essentially error free, (ii) daughter strand repair is error prone and (iii) additional undefined error-prone repair processes may exist. With gamma irradiation the sensitive ataxia telangiectasia cells are not hypermutable, these cells may then be defective in an error-prone repair process. Alternatively, induced mutants which have origin as chromosome deletions may prove lethal in such cells because of their susceptibility to the chromosome damaging effects of ionizing radiation. Photoreactivation was without effect on sister strand exchanges in a marsupial cell line. This result indicates that these chromosome effects are not caused by pyrimidine dimers but some other lesion. (Auth.)

  13. The proliferative effects of asbestos-exposed peripheral blood mononuclear cells on mesothelial cells

    Science.gov (United States)

    MAKI, YUHO; NISHIMURA, YASUMITSU; TOYOOKA, SHINICHI; SOH, JUNICHI; TSUKUDA, KAZUNORI; SHIEN, KAZUHIKO; FURUKAWA, MASASHI; MURAOKA, TAKAYUKI; UENO, TSUYOSHI; TANAKA, NORIMITSU; YAMAMOTO, HIROMASA; ASANO, HIROAKI; MAEDA, MEGUMI; KUMAGAI-TAKEI, NAOKO; LEE, SUNI; MATSUZAKI, HIDENORI; OTSUKI, TAKEMI; MIYOSHI, SHINICHIRO

    2016-01-01

    Malignant mesothelioma (MM) is thought to arise from the direct effect of asbestos on mesothelial cells. However, MM takes a long time to develop following exposure to asbestos, which suggests that the effects of asbestos are complex. The present study examined the effects of asbestos exposure on the cell growth of MeT-5A human mesothelial cells via cytokines produced by immune cells. Peripheral blood mononuclear cells (PBMCs) were stimulated with antibodies against cluster of differentiation (CD)3 and CD28 upon exposure to the asbestos chrysotile A (CA) or crocidolite (CR); the growth of MeT-5A cells in media supplemented with PBMC culture supernatants was subsequently examined. MeT-5A cells exhibited an increase in proliferation when grown in supernatant from the 7-day PBMC culture exposed to CA or CR. Analysis of cytokine production demonstrated increased levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-1α, IL-1β, IL-3, IL-5, IL-13 and IL-17A in supernatants. Individual administration of these cytokines, excluding G-CSF and GM-CSF, led to an increase in cell growth of MeT-5A, whereas this effect was not observed following the combined administration of these cytokines. The results indicate that cytokines secreted by immune cells upon exposure to asbestos cause an increase in the growth activity of mesothelial cells, suggesting that alterations in the production of cytokines by immune cells may contribute to tumorigenesis in individuals exposed to asbestos.

  14. Repair-deficient xeroderma pigmentosum cells made UV light resistant by fusion with X-ray-inactivated Chinese hamster cells

    International Nuclear Information System (INIS)

    Xeroderma pigmentosum (XP) is an autosomal recessive human disease, characterized by an extreme sensitivity to sunlight, caused by the inability of cells to repair UV light-induced damage to DNA. Cell fusion was used to transfer fragments of Chinese hamster ovary (CHO) chromosomes into XP cells. The hybrid cells exhibited UV resistance and DNA repair characteristics comparable to those expressed by CHO cells, and their DNA had greater homology with CHO DNA than did the DNA from XP cells. Control experiments consisted of fusion of irradiated and unirradiated XP cells and repeated exposure of unfused XP cells to UV doses used for hybrid selection. These treatments did not result in an increase in UV resistance, repair capability, or homology with CHO DNA. The hybrid cell lines do not, therefore, appear to be XP revertants. The establishment of these stable hybrid cell lines is an initial step toward identifying and cloning CHO DNA repair genes that complement the XP defect in human cells. The method should also be applicable to cloning genes for other diseases, such as ataxia-telangiectasia and Fanconi's anemia

  15. Alterations in Cellular Energy Metabolism Associated with the Antiproliferative Effects of the ATM Inhibitor KU-55933 and with Metformin

    OpenAIRE

    Zakikhani, Mahvash; Bazile, Miguel; Hashemi, Sina; Javeshghani, Shiva; Avizonis, Daina; Pierre, Julie St; Pollak, Michael N.

    2012-01-01

    KU-55933 is a specific inhibitor of the kinase activity of the protein encoded by Ataxia telangiectasia mutated (ATM), an important tumor suppressor gene with key roles in DNA repair. Unexpectedly for an inhibitor of a tumor suppressor gene, KU-55933 reduces proliferation. In view of prior preliminary evidence suggesting defective mitochondrial function in cells of patients with Ataxia Telangiectasia (AT), we examined energy metabolism of cells treated with KU-55933. The compound increased AM...

  16. Synergistic enhancement of NK cell-mediated cytotoxicity by combination of histone deacetylase inhibitor and ionizing radiation

    International Nuclear Information System (INIS)

    The overexpression of histone deacetylase (HDAC) and a subsequent decrease in the acetylation levels of nuclear histones are frequently observed in cancer cells. Generally it was accepted that the deacetylation of histones suppressed expression of the attached genes. Therefore, it has been suggested that HDAC might contribute to the survival of cancer cells by altering the NKG2D ligands transcripts. By the way, the translational regulation of NKG2D ligands remaines unclear in cancer cells. It appears the modulation of this unclear mechanism could enhance NKG2D ligand expressions and the susceptibility of cancer cells to NK cells. Previously, it was reported that irradiation can increase the surface expressions of NKG2D ligands on several cancer cell types without increasing the levels of NKG2D ligand transcripts via ataxia telangiectasia mutated and ataxia telangiectasia and Rad3 related (ATM-ATR) pathway, and suggested that radiation therapy might be used to increase the translation of NKG2D ligands. Two NSCLC cell lines, that is, A549 and NCI-H23 cells, were used to investigate the combined effects of ionizing radiation and HDAC inhibitors on the expressions of five NKG2D ligands. The mRNA expressions of the NKG2D ligands were quantitated by multiplex reverse transcription-PCR. Surface protein expressions were measured by flow cytometry, and the susceptibilities of cancer cells to NK cells were assayed by time-resolved fluorometry using the DELFIA® EuTDA cytotoxicity kit and by flow cytometry. The expressions of NKG2D ligands were found to be regulated at the transcription and translation levels. Ionizing radiation and HDAC inhibitors in combination synergistically increased the expressions of NKG2D ligands. Furthermore, treatment with ATM-ATR inhibitors efficiently blocked the increased translations of NKG2D ligands induced by ionizing radiation but did not block the increased ligand translations induced by HDAC inhibitors. The study confirms that increased NKG

  17. Chronic γ-irradiation results in increased cell killing and chromosomal aberration with specific breakpoints in fibroblast cell strains derived from non-Hodgkin's lymphoma patients

    International Nuclear Information System (INIS)

    Cultured skin fibroblast cells from 16 NHL (non-Hodgkin's lymphoma) patients and 2 clinically normal subjects were compared for cell survival and chromosomal aberration after chronic γ-irradiation. Fibroblasts from an ataxia telangiectasia (AT) homozygote and an AT heterozygote were used as positive controls. Following irradiation, fibroblasts from all 16 NHL patients showed an increase in both cell death and chromosomal aberration (breaks and rearrangements) compared to normal subjects. The difference in frequency of chromosomal aberration between normals and NHL-patients remained virtually unchanged over a period of 24-72 h post irradiation incubation of cells. Cell cycle analysis by flow cytometry carried out in 1 normal and 1 NHL fibroblast cell strain showed that more cells representing the NHL patient were in G2/M phase compared to the normal at various times of cytogenetic analysis. While the AT homozygote appeared to be the most radiosensitive, the AT heterozygote showed a slightly higher incidence of cell death and chromosomal aberration than the normals. The cellular and chromosomal radiosensitivity of fibroblast cell lines from NHL-patients differed slightly from that of AT heterozygote but clearly occupied an intermediate position between the AT homozygote and the normal subjects. Cells from 3 of the NHL patients showed radiation-induced specific chromosomal breaks involving chromosomes 1, 2, 6, 8, 10 and 11 which correspond to known fragile sites. Such breakpoints associated with increased radiosensitivity may be indicative of predisposition to malignancy in the patients studied. (author). 30 refs., 2 figs., 4 tabs

  18. Expression and function of aquaporin-1 in hyperoxia-exposed alveolar epithelial type II cells

    OpenAIRE

    ZHANG, QIU-YUE; Fu, Jian-Hua(Department of Physics, Henan University of Technology, Zhengzhou 450001, China); XUE, XIN-DONG

    2014-01-01

    The aim of the present study was to investigate water transport dysfunction in alveolar epithelial type II cells (AECII), which were exposed to hyperoxia, and to investigate the mechanism of pulmonary edema resulting from hyperoxic lung injury. The lung cells of newborn rats were isolated for primary cell culture and divided into control and experimental groups. The control and experimental group cells were placed into a normoxic incubator (oxygen volume fraction, 0.21) or hyperoxic incubator...

  19. Multiplication of human NHIK 3025 cells exposed to porphyrins in combination with light.

    OpenAIRE

    Christensen, T.

    1981-01-01

    Cells from the established line NHIK 3025 were exposed to haematoporphyrin derivative and light. After this photodynamic treatment the first interphase of surviving cells was prolonged. Furthermore, a pronounced effect on the progression through the first mitosis was observed. Mainly the duration of metaphase was increased. Some of the cells were irreversibly arrested in mitosis and the cells that were able to complete mitosis after treatment multiplied in the subsequent generations at the sa...

  20. DNA Fragmentation in mammalian cells exposed to various light ions

    Science.gov (United States)

    Belli, M.; Cherubini, R.; Dalla Vecchia, M.; Dini, V.; Esposito, G.; Moschini, G.; Sapora, O.; Signoretti, C.; Simone, G.; Sorrentino, E.; Tabocchini, M. A.

    Elucidation of how effects of densely ionizing radiation at cellular level are linked to DNA damage is fundamental for a better understanding of the mechanisms leading to genomic damage (especially chromosome aberrations) and developing biophysical models to predict space radiation effects. We have investigated the DNA fragmentation patterns induced in Chinese hamster V79 cells by 31 keV/μm protons, 123 keV/μm helium-4 ions and γ-rays in the size range 0.023-5.7 Mbp, using calibrated Pulsed Field Gel Electrophoresis (PFGE). The frequency distributions of fragments induced by the charged particles were shifted towards smaller sizes with respct to that induced by comparable doses of γ-rays. The DSB yields, evaluated from the fragments induced in the size range studied, were higher for protons and helium ions than for γ-rays by a factor of about 1.9 and 1.2, respectively. However, these ratios do not adequately reflect the RBE observed on the same cells for inactivation and mutation induced by these beams. This is a further indication for the lack of correlation between the effects exerted at cellular level and the initial yield of DSB. The dependence on radiation quality of the fragmentation pattern suggests that it may have a role in damage reparability. We have analyzed these patterns with a "random breakage" model generalized in order to consider the initial non-random distribution of the DNA molecules. Our results suggest that a random breakage mechanism can describe with a reasonable approximation the DNA fragmentation induced by γ-rays, while the approximation is not so good for light ions, likely due to the interplay between ion tracks and chromatin organization at the loop level.

  1. Genetic effect of low dose rate radiation on human cells immortalized with the hTERT gene

    International Nuclear Information System (INIS)

    We established immortal human cells by introducing the hTERT gene into skin fibroblast cells obtained from normal (SuSa) and ataxia telangiectasia (AT: AT1OS) individuals of Japanese origin. These immortalized cells showed the same characteristics as the original cells except expanded life span. We irradiated SuSa/T-n and AT1OS/T-n cells with low-dose-rate (LDR; 0.3 mGy/min) irradiation at confluent state in low-serum medium. Then, survival rate and micronucleus frequency of each cell line were analyzed. In SuSa/T-n cells, frequency of HPRT mutation induction was also determined by 6TG selection. In SuSa/T-n cells, survival rate and micronucleus frequency showed higher resistance after irradiation with LDR than high-dose-rate (HDR; 2 Gy/min) irradiation. In contrast, no significant difference was observed in survival and micronucleus induction in AT1OS/T-n cells between HDR and LDR irradiation, suggesting that AT1OS/T-n cells may have some defect in DNA repair activity. In SuSa/T-n cells, the frequency of HPRT mutation after LDR irradiation decreased to approximately one eighth that after HDR irradiation. (author)

  2. Spontaneous loss and alteration of antigen receptor expression in mature CD4+ T cells

    International Nuclear Information System (INIS)

    The T-cell receptor CD3 (TCR/CD3) complex plays a central role in antigen recognition and activation of mature T cells, and therefore abnormalities in the expression of the complex should induce unresponsiveness of T cells to antigen stimulus. Using flow cytometry, we detected and enumerated variant cells with loss or alteration of surface TCR/CD3 expression among human mature CD4+ T cells. The presence of variant CD4+ T cells was demonstrated by isolating and cloning them from peripheral blood, and their abnormalities can be accounted for by alterations in TCR expression such as defects of protein expression and partial protein deletion. The variant frequency in peripheral blood increased with aging in normal donors and was highly elevated in patients with ataxia telangiectasia, an autosomal recessive inherited disease with defective DNA repair and variable T-cell immunodeficiency. These findings suggest that such alterations in TCR expression are induced by somatic mutagenesis of TCR genes and can be important factors related to age-dependent and genetic disease-associated T-cell dysfunction. (author)

  3. In vitro cell-mediated immunity studies of plutonium-exposed beagle dogs

    International Nuclear Information System (INIS)

    Mitogen-induced activation was measured in spleen and mesenteric lymph node cell preparations from dogs exposed to a single inhalation exposure of plutonium oxide (238Pu or 239Pu). Reduced stimulation indices of splenic lymphocytes from exposed animals suggest that a reduction in lymphocyte function has occurred in this tissue. No apparent reduction in mitogen stimulation indices was observed in mesenteric lymph node cultures

  4. Mitochondrial oxidative stress in human hepatoma cells exposed to stavudine

    International Nuclear Information System (INIS)

    The toxicity of nucleoside reverse transcriptase inhibitors (NRTIs) is linked to altered mitochondrial DNA (mtDNA) replication and subsequent disruption of cellular energetics. This manifests clinically as elevated concentrations of lactate in plasma. The mechanism(s) underlying how the changes in mtDNA replication lead to lactic acidosis remains unclear. It is hypothesized that mitochondrial oxidative stress links the changes in mtDNA replication to mitochondrial dysfunction and ensuing NRTIs toxicity. To test this hypothesis, changes in mitochondrial function, mtDNA amplification efficiency, and oxidative stress were assessed in HepG2-cultured human hepatoblasts treated with the NRTI stavudine (2',3'-didehydro-2',3'-deoxythymidine or d4T) for 48 h. d4T produced significant mitochondrial dysfunction with a 1.5-fold increase in cellular lactate to pyruvate ratios. In addition, d4T caused a dose-dependent decrease in mtDNA amplification and a correlative increase in abundance of markers of mitochondrial oxidative stress. Manganese (III) meso-tetrakis (4-benzoic acid) porphyrin, MnTBAP, a catalytic antioxidant, ameliorated or reversed d4T-induced changes in cell injury, energetics, mtDNA amplification, and mitochondrial oxidative stress. In conclusion, d4T treatment elevates mitochondrial reactive oxygen species (ROS), enhances mitochondrial oxidative stress, and contributes mechanistically to NRTI-induced toxicity. These deleterious events may be potentiated in acquired immunodeficiency syndrome (AIDS) by human immunodeficiency virus (HIV) infection itself, coinfection (e.g., viral hepatitis), aging, substance, and alcohol use

  5. The role of DNA repair on cell killing by charged particles

    Science.gov (United States)

    Eguchi-Kasai, K.; Murakami, M.; Itsukaichi, H.; Fukutsu, K.; Kanai, T.; Furusawa, Y.; Sato, K.; Ohara, H.; Yatagai, F.

    It can be noted that it is not simple double strand breaks (dsb) but the non-reparable breaks that are associated with high biological effectiveness in the cell killing effect for high LET radiation. Here, we have examined the effectiveness of fast neutrons and low (initial energy = 12 MeV/u) or high (135 MeV/u) energy charged particles on cell death in 19 mammalian cell lines including radiosensitive mutants. Some of the radiosensitive lines were deficient in DNA dsb repair such as LX830, M10, V3, and L5178Y-S cells and showed lower values of relative biological effectiveness (RBE) for fast neutrons if compared with their parent cell lines. The other lines of human ataxia-telangiectasia fibroblasts, irs 1, irs 2, irs 3 and irs1SF cells, which were also radiosensitive but known as proficient in dsb repair, showed moderate RBEs. Dsb repair deficient mutants showed low RBE values for heavy ions. These experimental findings suggest that the DNA repair system does not play a major role against the attack of high linear energy transfer (LET) radiations. Therefore, we hypothesize that a main cause of cell death induced by high LET radiations is due to non-reparable dsb, which are produced at a higher rate compared to low LET radiations.

  6. Comparison of γ i-irradiation-induced accumulation of ataxia telangiesctasia and control cells in G2 phase

    International Nuclear Information System (INIS)

    Recent reports from a number of laboratories have linked radiosensitivity in ataxia telangiectasia (AT) to a large and prolonged block of some cells in G2 phase. Previous results from this laboratory, largely with one Epstein-Barr virus-transformed A-T lymphoblastoid cell line, presented evidence for a dramatic increase in the number of cells in G2 phase over controls during a 24 h period post irradiation. We describe here a study of the effect of γ-radiation on G2 phase delay in several A-T cell lines. Based on previous results with several cell lines 24 h post irradiation was selected as the optimum time to discriminate between G2 phase delay in control and A-T cells. All A-T homozygotes showed a signigicantly greater number of cells in G2 phase, 24 h post irradiation, than observed in controls. A more prolonged delay in G2 phase after irradiation was seen in different A-T cell types that included lymphoblastoid cells, fibroblasts and SV40-transformed fibroblasts. At the radiation dose used it was not possibel to distinguish A-T heterozygotes from controls (Author). 28 refs.; 2 figs.; 1 tab

  7. Modeling the role of p53 pulses in DNA damage- induced cell death decision

    Directory of Open Access Journals (Sweden)

    Cui Jun

    2009-06-01

    Full Text Available Abstract Background The tumor suppressor p53 plays pivotal roles in tumorigenesis suppression. Although oscillations of p53 have been extensively studied, the mechanism of p53 pulses and their physiological roles in DNA damage response remain unclear. Results To address these questions we presented an integrated model in which Ataxia-Telangiectasia Mutated (ATM activation and p53 oscillation were incorporated with downstream apoptotic events, particularly the interplays between Bcl-2 family proteins. We first reproduced digital oscillation of p53 as the response of normal cells to DNA damage. Subsequent modeling in mutant cells showed that high basal DNA damage is a plausible cause for sustained p53 pulses observed in tumor cells. Further computational analyses indicated that p53-dependent PUMA accumulation and the PUMA-controlled Bax activation switch might play pivotal roles to count p53 pulses and thus decide the cell fate. Conclusion The high levels of basal DNA damage are responsible for generating sustained pulses of p53 in the tumor cells. Meanwhile, the Bax activation switch can count p53 pulses through PUMA accumulation and transfer it into death signal. Our modeling provides a plausible mechanism about how cells generate and orchestrate p53 pulses to tip the balance between survival and death.

  8. Luteolin Impacts on the DNA Damage Pathway in Oral Squamous Cell Carcinoma.

    Science.gov (United States)

    Tjioe, Kellen Cristine; Tostes Oliveira, Denise; Gavard, Julie

    2016-07-01

    Oral squamous cell carcinoma (OSCC) exhibited high chemoresistance to current treatments. Here we aimed at identifying and repositioning approved drugs that could be selectively toxic toward OSCC cells. Through a cell-based drug screening of 1,280 chemical molecules, we selected compounds lethal to oral cancer SCC-25 cells, while sparing normal keratinocyte HaCaT cells. Within the chemical library, the natural flavonoid luteolin was identified as a potent cytotoxic agent against oral cancer cells in vitro, along with metixene hydrochloride and nitazoxanide. Of note, they exhibit low toxicity and high efficiency compared to the standard-of-care, such as cisplatin and the epidermal growth factor receptor inhibitor tyrphostin. From a molecular standpoint, luteolin causes phosphorylation of ataxia telangiectasia mutated (ATM) and H2AX in a DNA repair pathway and can be efficiently combined with a checkpoint kinase (CHK) pharmacological inhibitor. Thus, luteolin emerges as a potent cytotoxic and/or adjuvant therapy in oral cancer, as it is a natural compound presenting better effects in vitro compared to conventional chemotherapeutic agents. Future in vivo exploration is next required to provide the proof-of-concept that luteolin could be an efficient anticancer molecule. PMID:27266882

  9. The study of responses to 'model' DNA breaks induced by restriction endonucleases in cells and cell-free systems: achievements and difficulties

    International Nuclear Information System (INIS)

    The use of restriction endonucleases (RE) as a means of implicating DNA double-strand breaks (dsb) in cellular responses is reviewed. The introduction of RE into cells leads to many of the responses known to be characteristic of radiation damage -cell killing, chromosomal aberration, oncogenic transformation, gene mutation and amplification. Additionally, radiosensitive cell lines are hypersensitive to RE, including those from the human disorder ataxia-telangiectasia. However, quantitation of response and comparisons of the effectiveness of different RE are difficult, partly because of unknown activity and lifetime of RE in the cell. Re-induced dsb have also been used to reveal molecular mechanisms of repair and misrepair at specific sites in DNA. Dsb have been implicated in recombination processes including those leading to illegitimate rejoining (formation of deletions and rearrangements) at short sequence features in DNA. Also model dsb act as a signal to activate other cellular processes, which may influence or indirectly cause some responses, including cell death. In these signalling responses the detailed chemistry at the break site may not be very important, perhaps explaining why there is considerable overlap in responses to RE and to ionizing radiations. (author)

  10. The ATM and ATR inhibitors CGK733 and caffeine suppress cyclin D1 levels and inhibit cell proliferation

    International Nuclear Information System (INIS)

    The ataxia telangiectasia mutated (ATM) and the ATM- related (ATR) kinases play a central role in facilitating the resistance of cancer cells to genotoxic treatment regimens. The components of the ATM and ATR regulated signaling pathways thus provide attractive pharmacological targets, since their inhibition enhances cellular sensitivity to chemo- and radiotherapy. Caffeine as well as more specific inhibitors of ATM (KU55933) or ATM and ATR (CGK733) have recently been shown to induce cell death in drug-induced senescent tumor cells. Addition of these agents to cancer cells previously rendered senescent by exposure to genotoxins suppressed the ATM mediated p21 expression required for the survival of these cells. The precise molecular pharmacology of these agents however, is not well characterized. Herein, we report that caffeine, CGK733, and to a lesser extent KU55933, inhibit the proliferation of otherwise untreated human cancer and non-transformed mouse fibroblast cell lines. Exposure of human cancer cell lines to caffeine and CGK733 was associated with a rapid decline in cyclin D1 protein levels and a reduction in the levels of both phosphorylated and total retinoblastoma protein (RB). Our studies suggest that observations based on the effects of these compounds on cell proliferation and survival must be interpreted with caution. The differential effects of caffeine/CGK733 and KU55933 on cyclin D1 protein levels suggest that these agents will exhibit dissimilar molecular pharmacological profiles

  11. Correlativity study between expression of DNA double-strand break repair protein and radiosensitivity of tumor cells

    Institute of Scientific and Technical Information of China (English)

    Liang ZHUANG; Shiying YU; Xiaoyuan HUANG; Yang CAO; Huihua XIONG

    2009-01-01

    DNA double-strand break (DSB) is generally regarded as the most lethal of all DNA lesions after radiation. KuS0, DNA-PK catalytic subunit (DNA-PKcs) and ataxia telangiectasia mutated (ATM) proteins are major DSB repair proteins. In this study, survival fraction at 2Gy (SF2) values of eight human tumor cell lines (including four human cervical carcinoma cell lines HeLa, SiHa, C33A, Caski, three human breast carcinoma cell lines MCF-7, MDA-MB-231, MDA-MB-453, and one human lung carcinoma cell line A549) were acquired by clone formation assay, and western blot was applied to detect the expressions of Ku80, DNA-PKcs and ATM protein. The correlativity of protein expression with SF2 value was analyzed by Pearson linear correlation analysis. We found that the expression of the same protein in different cell lines and the expression of three proteins in the same cell line had a significant difference. The SF2 values were also different in eight tumor cell lines and there was a positive correlativity between the expression of DNA-PKcs and SF2 (r=0.723, P =0.043), but Ku80 and ATM expression had no correlation with SF2 (P>0.05). These findings suggest that the expression level of DNA-PKcs protein can be an indicator for predicting the radiosensitivity of tumor cells.

  12. Micronucleus frequency in exfoliated buccal cells from hairdresser who expose to hair products

    Directory of Open Access Journals (Sweden)

    Koh Hui Yee

    2015-06-01

    Full Text Available Background: Hairdresser is one of the fastest growing occupations in today’s society. Hairdresser help styling, cutting, colouring, perming, curling, straightening hair and various treatment to customer. Somehow, hairdresser are constantly exposed to chemical substances such as aromatic amines, hydrogen peroxide, thioglycolic acid, formaldehyde in hair products which can cause damage to human’s genome. Micronucleus is one of the effective biomarker for processes associated with the induction of DNA damage. Purpose: The aim of this study was to determine the micronucleus frequencies in buccal mucosa epithelial cells of hairdresser who were exposed to chemical of hair products. Method: This study was conducted on twenty female subjects, who were divided into 2 groups: exposed and non-exposed (control group. All subjects recruited were working in the same beauty salon. Buccal cells were obtained from each individual by using cytobrush. The cells were stained with modified Feulgen-Ronssenback method and counting of micronucleus per 1000 cell was done under light microscope. The data were analyzed using independent t-test and one-way Anova (p<0.05. Result: The result showed a significant difference in micronucleus frequency between 2 groups. There were a significantly increase of micronucleus frequency in hairdressers and increase of  micronucleus frequency with the longer duration of exposure. Conclusion: It concluded that the chemical substances of hair products had affected the micronucleus frequency ofthe epithelial cells in buccal mucosa of hairdressers.

  13. Repair of DNA damage induced by ionizing radiation and benzo[a]pyrene in mammalian cells

    International Nuclear Information System (INIS)

    The biological effects of DNA-damaging agents are codetermined by the structural characteristics of the lesions, the quality and extent of the local distortion of DNA and chromatin structure, and the mode(s) of damage processing used by a given type of cell. Persistent damage (i.e., damage that is not removed before it is reached by DNA replication) may be mostly responsible for mutagenesis and carcinogenesis. To understand the effects of environmental physical and chemical DNA-damaging agents on human health, the mechanisms of damage processing used by human cells have to be elucidated. We report our studies of the excision of gamma-ray products of the 5,6-dihydroxydihydrothymine type (t0/sub 2//sup γ/) in normal human fibroblasts and in fibroblasts from patients with the hereditary diseases Fanconi's anemia (FA) and ataxia telangiectasia (AT). Both diseases are characterized by chromosomal instability and increased susceptibility for the development of cancer. Formation and repair of DNA-benzo[a]pyrene adducts were studied in baby hamster kidney cells, secondary mouse embryo cells, and human lymphoma. The relative persistence of DNA-B[a]P may explain the high mutagenicity of the 7,8-dihydroxy-9,10-epoxy-tetrahydrobenzo[a]pyrene metabolites in rodent cells that has been observed by several investigators

  14. Expression of x-irradiated prokaryotic genes after transfection in primate cells

    International Nuclear Information System (INIS)

    X-irradiated rhoSC2CAT plasmids were transfected into monkey CV-1 and COS-7 cells and human fibroblast cells. Transient expression assays for chloramphenicol acetyltransferase (CAT) showed that expression from irradiated plasmids decreased with the same D/sub o/ as the x-ray conversion of circular forms to linear molecules of unit length, i.e., 13 Gy after irradiation in water or 270 Gy after irradiation in 1 mM Tris buffer. Loss of supercoiled forms was complete at much lower radiation doses than were required to inhibit CAT expression. In rhoSV2CAT one radiation linearization event after x-irradiation in water was associated with 6.5 single strand breaks. A single linearization event by Bam H1 at a site outside the CAT gene reduced CAT expression to 5% of control values, suggesting that circular or supercoiled plasmids are favored for expression. Expression of irradiated plasmids in cell lines established from patients with ataxia telangiectasia (AT), xeroderma pigmentosum (XP), and from normal subjects were compared. Certain repair deficient cell lines exhibited markedly reduced capacity to express unirradiated or irradiated pSV2CAT. The results indicate a useful new way to judge the complete expression of genes after minimal x-ray damage to the DNA, by introducing the genes into unirradiated cells of differing DNA repair capacities

  15. Prediction of human cell radiosensitivity: Comparison of clonogenic assay with chromosome aberrations scored using premature chromosome condensation with fluorescence in situ hybridization

    International Nuclear Information System (INIS)

    The purpose of the present investigation was to determine whether chromosome aberrations scored by premature chromosome condensation (PCC) and fluorescence in situ hybridization (FISH) can predict the radiosensitivity of human cell lines, thereby providing a possible means of assessing the in situ radiosensitivity of normal tissues and the radiocurability of individual human cancers. We used four cells lines of different radiosensitivity: normal human fibroblasts (AG1522), ataxia-telangiectasia fibroblasts (AT2052), a human fibrosarcoma cell line (HT1080), and a human melanoma cell line (melanoma 903). These were irradiated in plateau phase with a range of doses and assessed both for clonogenic cell survival and for aberrations in a single chromosome (number 4) immediately after, and 24 h after irradiation. The initial number of breaks in chromosome 4 was proportional to irradiation dose and was identical for all the different human cell lines, irrespective of radiosensitivity. On the other hand, the number of chromosome 4 breaks remaining 24 h after irradiation reflected the radiosensitivity of the cells such that the relationship between residual chromosome aberrations and cell survival was the same for the different cell lines. These results suggest that the scoring of chromosome aberrations in interphase using FISH with PCC holds considerable promise for predicting the radiosensitivity of normal and tumor tissues in situ. 28 refs., 4 figs

  16. Determining adaptive and adverse oxidative stress responses in human bronical epithelial cells exposed to zinc

    Science.gov (United States)

    Determining adaptive and adverse oxidative stress responses in human bronchial epithelial cells exposed to zincJenna M. Currier1,2, Wan-Yun Cheng1, Rory Conolly1, Brian N. Chorley1Zinc is a ubiquitous contaminant of ambient air that presents an oxidant challenge to the human lung...

  17. Immune cells in Chernobyl radiation workers exposed to low-dose irradiation

    International Nuclear Information System (INIS)

    the aim of this work was to study immune response parameters in Chernobyl emergency and recovery operation radiation workers and nuclear industry workers exposed under professional limits. The monohydroxylated fatty acid content in peripheral blood mononuclear cell of radiation workers compared to unexposed control at the 12-th year after Chernobyl NPP accident was studied too

  18. Cultured diploid fibroblasts from patients with the nevoid basal cell carcinoma syndrome are hypersensitive to killing by ionizing radiation

    International Nuclear Information System (INIS)

    Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disease. About 20% of the gene carriers studied developed medulloblastoma before the age of 5 years. Clinical follow-up of these patients, treated with radiotherapy, revealed a predisposition to radiogenic basal cell carcinomas with an unusually short latent period of 6 months to 3 years. The authors have therefore cultured skin fibroblasts from 5 NBCCS patients and measured their radiosensitivity in terms of clonogenic survival. Our results showed that, compared with 6 normal controls, the NBCCS cells were hypersensitive to X-rays. The average D0 (the inverse of the slope of the survival curve) for the NBCCS cells was 98 rads, compared with 142 rads for the normal controls and 44 rads for an ataxia telangiectasia (AT) strain. The average D10 values (the dose required to reduce survival to 10%) were 258, 351, and 123 rads for the NBCCS, normal, and AT strains, respectively. Unscheduled DNA synthesis measurements showed that NBCCS cells were not defective in excision repair of X-ray-damaged DNA. Pulse labeling index measurements showed that NBCCS cells were abnormally inhibited in the initiation of DNA synthesis following X-irradiation. The mechanisms underlying the radiosensitivity of NBCCS differ in several respects from those of AT. NBCCS appears to be potentially a useful model for studying the cellular processes that are important in radiation carcinogenesis

  19. Establishment and characterization of two human cell lines with amplified dihydrofolate reductase genes

    International Nuclear Information System (INIS)

    Two SV40-transformed human cell lines, GM637, derived from a normal human subject, and GM5849, derived from a patient with ataxia-telangiectasia (A-T), were grown in increasing concentrations of the cytotoxic agent methotrexate (MTX). The GM637 line was naturally more resistant to methotrexate than was GM5849 and, over a 5-month period, became resistant even to very high concentrations (up to 100 μM). The GM5849 line became resistant to 500 nM methotrexate during the same period. However, dot blot and Southern blot analyses showed that both cell lines had amplified their dihydrofolate reductase (dhfr) genes to about the same extent, approx. 50-fold. Using the GM5849 line with amplified dhrf, the authors attempted to determine if interruption of DNA synthesis by hydroxyurea would cause DNA to be replicated twice within a single cell cycle, as has been reported for Chinese hamster ovary cells. No evidence for such a phenomenon was obtained

  20. p53-Dependent Adaptive Responses in Human Cells Exposed to Space Radiations

    International Nuclear Information System (INIS)

    Purpose: It has been reported that priming irradiation or conditioning irradiation with a low dose of X-rays in the range of 0.02-0.1 Gy induces a p53-dependent adaptive response in mammalian cells. The aim of the present study was to clarify the effect of space radiations on the adaptive response. Methods and Materials: Two human lymphoblastoid cell lines were used; one cell line bears a wild-type p53 (wtp53) gene, and another cell line bears a mutated p53 (mp53) gene. The cells were frozen during transportation on the space shuttle and while in orbit in the International Space Station freezer for 133 days between November 15, 2008 and March 29, 2009. After the frozen samples were returned to Earth, the cells were cultured for 6 h and then exposed to a challenging X-ray-irradiation (2 Gy). Cellular sensitivity, apoptosis, and chromosome aberrations were scored using dye-exclusion assays, Hoechst33342 staining assays, and chromosomal banding techniques, respectively. Results: In cells exposed to space radiations, adaptive responses such as the induction of radioresistance and the depression of radiation-induced apoptosis and chromosome aberrations were observed in wtp53 cells but not in mp53 cells. Conclusion: These results have confirmed the hypothesis that p53-dependent adaptive responses are apparently induced by space radiations within a specific range of low doses. The cells exhibited this effect owing to space radiations exposure, even though the doses in space were very low.

  1. Host cell reactivation of uv- and X-ray-damaged herpes simplex virus by Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines

    International Nuclear Information System (INIS)

    The efficacy of using an infected centers assay, employing herpes simplex virus-infected, Epstein-Barr virus-transformed lymphoblastoid cell lines (LCLs) as components, to study host cell reactivation has been explored. Herpes simplex virus type 1 (HSV-1) was shown through the infected centers assay to have detectable but varying ability to lytically infect LCLs established from chromosomal breakage syndromes or closely related genetic disorders. The rate of HSV inactivation by ultraviolet (uv) irradiation was faster in LCLs established from Cockaynes's syndrome than in normal LCLs, and faster still in LCLs established from xeroderma pigmentosum. These results indicate that Cockayne's syndrome, while having what appears to be quantitatively normal levels of uv-induced DNA repair replication, shows decreased ability to host cell reactivated uv-damaged HSV. In direct contrast, X-irradiated HSV showed identical survival when assayed on normal LCLs or LCLs established from ataxia telangiectasia showing increased sensitivity to X irradiation as measured by colony formation. Through the infected centers assay, it has also been possible to demonstrate low levels of multiplicity reactivation of mutagen-damaged HSV in permanently proliferating LCLs

  2. In vivo ultraviolet-exposed human epidermal cells activate T suppressor cell pathways that involve CD4+CD45RA+ suppressor-inducer T cells

    International Nuclear Information System (INIS)

    In vivo UV exposure of human epidermis abrogates the function of CD1+DR+ Langerhans cells and induces the appearance of CD1-DR+ Ag-presenting macrophages. Epidermal cells from UV-exposed skin, in contrast to epidermal cells from normal skin, potently activate autologous CD4+ T cells, and, in particular, the CD45RA+ (2H4+) (suppressor-inducer) subset. We therefore determined whether UV-exposure in humans leads to a T cell response in which suppression dominates. Autologous blood T cells were incubated with epidermal cell suspensions from in vivo UV-irradiated skin. After activation, repurified T cells were transferred in graded numbers to autologous mononuclear cells (MNC) stimulated with PWM and the resultant IgG production analyzed by ELISA. Relative to T cells activated by unirradiated control epidermal cells, T cells activated by UV-exposed epidermal cells demonstrated enhanced capacity to suppress IgG production (n = 6; p less than or equal to 0.03). Within the T cell population, CD8+ cells stimulated by UV-exposed epidermal cells could be directly activated to suppress PWM-stimulated MNC Ig production if IL-2 was provided in the reaction mixture. The suppressive activity was also transferable with purified CD4+ T cells stimulated by UV-exposed epidermal cells (n = 10; p less than or equal to 0.01), and was radiosensitive. Suppression was decreased when PWM-stimulated MNC were depleted of CD8+ T cells before mixing with CD4+ T cells activated by UV-exposed epidermal cells, suggesting indirect induction of CD8+ Ts cells contained within the responding MNC populations. Indeed, physical depletion of CD45RA+ cells resulted in total abrogation of the suppressor function contained in the CD4+ T cells. Activation of suppressor function was critically dependent on DR+ APC contained in UV-exposed epidermis

  3. Photoreactivation of ICR 2A frog cells exposed to solar UV wavelengths

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to photoreactivating light (PRL) following irradiation with a fluorescent sun lamp (FSL) results in an enhancement in survival compared with FSL-irradiated cells incubated in the dark. Hence, pyrimidine dimers played a role in the killing of cells exposed to the UV produced by this source. However, when the light was passed through a series of filters to remove increasing segments of the wavelength region shorter than 320 nm, the effect of the PRL progressively decreased, demonstrating that non-dimer photoproducts play an increasingly important role in the killing of cells exposed to wavelengths approaching 320 nm. Cells were also exposed to 313 nm UV produced by a monochromator and it was found, once again, that the effectiveness of the PRL treatment depended on the filter the beam was passed through. These results indicate that for both FSL-produced UV and 313 nm UV emitted by a monochromator, that the critical photoproducts within the cell depend on the filter used in conjuction with the UV source. (author)

  4. Study on the characteristics of cell-cycle perturbation in hela cell exposed to continuous β irradiation of 32P

    International Nuclear Information System (INIS)

    In an attempt to understand radiobiological basis for targeted radiotherapy in oncology, the cell cycle perturbations have studied in Hela cell lines after exposed to different doses and dose-rate of 32P radiation. Asynchronous Hela cells, cultured in vitro, were exposed to β radiation from radioactive filter papers (absorbed 32P) which were put close under culture plate of growing monolayer of Hela cells. The characteristic radiation response to different dose, dose-rate and radiation time was evaluated through cell cycle perturbation studied by flow cytometry. Cell cycle status showed G2 phase blockage in a way of dose dependence, a plateau of G2 block can be recognized at about 24h. Interestingly, the G2 phase declined even though the accumulated doses increased as the time of radiation prolonged. This result suggested that the cell cycle progress could not be inhibited completely when exposed to continuous radiation, rather it seems to be controlled somehow by the nature of cell cycle itself for a certain cell line. G2 blockage, one of the major changes caused by β radiation, is dose-dependent, but the time reaching the plateau of G2 phase blockage is most likely related with the intrinsic nature of cell cycle

  5. Vanillin protects human keratinocyte stem cells against ultraviolet B irradiation.

    Science.gov (United States)

    Lee, Jienny; Cho, Jae Youl; Lee, Sang Yeol; Lee, Kyung-Woo; Lee, Jongsung; Song, Jae-Young

    2014-01-01

    Ultraviolet-B (UVB) irradiation is one of major factors which induce cellular damages in the epidermis. We investigated protective effects and mechanisms of vanillin, a main constituent of vanilla beans, against UVB-induced cellular damages in keratinocyte stem cells (KSC). Here, vanillin significantly attenuated UVB irradiation-induced cytotoxicity. The vanillin effects were also demonstrated by the results of the senescence-associated β-galactosidase and alkaline comet assays. In addition, vanillin induced production of pro-inflammatory cytokines. Attempts to elucidate a possible mechanism underlying the vanillin-mediated effects revealed that vanillin significantly reduced UVB-induced phosphorylation of ataxia telangiectasia mutated (ATM), serine threonine kinase checkpoint kinase 2 (Chk2), tumor suppressor protein 53 (p53), p38/mitogen-activated protein kinase (p38), c-Jun N-terminal kinase/stress-activated protein kinase (JNK), S6 ribosomal protein (S6RP), and histone 2A family member X (H2A.X). UVB-induced activation of p53 luciferase reporter was also significantly inhibited by vanillin. In addition, while ATM inhibitor had no effect on the vanillin effects, mouse double minute 2 homolog (MDM2) inhibitor significantly attenuated suppressive effects of vanillin on UVB-induced activation of p53 reporter in KSC. Taken together, these findings suggest that vanillin protects KSC from UVB irradiation and its effects may occur through the suppression of downstream step of MDM2 in UVB irradiation-induced p53 activation. PMID:24184596

  6. Effect of space flight on the frequency of micronuclei and expression of stress-responsive proteins in cultured mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Ikenaga, Mituo; Hirayama, Jun; Kato, Tomohisa [Kyoto Univ. (Japan). Radiation Biology Center] [and others

    2002-12-01

    Results of past space experiments suggest that the biological effect of space radiation could been hanced under microgravity in some cases, especially ininsects. To examine if such a synergistic effect of radiation and microgravity also exists in human cells, frequencies of chromosome instability and cellular levels of several stress-responsive proteins were analyzed incultured human and rodent cells afterspace flight. Human (MCF7 and ataxia telangiectasia(AT)2KY), mouse (m5S) and hamster (Syrian hamster embryo (SHE)) cell lines were loaded on the Space Shuttle Discovery (STS-95 mission) and grown during a 9-daymission. After landing, the micronuclei resulting from abnormal nuclear division and accumulationof stress-responsive proteins such as p53 and mitogen-activated protein kinases (MAPKs), which are involved in radiation-induced signal transduction cascades, were analyzed. The frequencies of micronucleiin all the four mammalian cell strains tested were not significantly different between flight and ground control samples. Also, the cellular amounts of p53, p21 (WAF1/SDI1/CIP1) and activated (phosphorylated) forms of three distinct MAPKs in MCF7 and m5S cells of flight samples were similar to those of ground control samples. These results indicated that anyeffect of space radiation, microgravity, or combination of both were not detectable, at least under thepresent experimental conditions. (author)

  7. Effect of space flight on the frequency of micronuclei and expression of stress-responsive proteins in cultured mammalian cells

    International Nuclear Information System (INIS)

    Results of past space experiments suggest that the biological effect of space radiation could been hanced under microgravity in some cases, especially ininsects. To examine if such a synergistic effect of radiation and microgravity also exists in human cells, frequencies of chromosome instability and cellular levels of several stress-responsive proteins were analyzed incultured human and rodent cells afterspace flight. Human (MCF7 and ataxia telangiectasia(AT)2KY), mouse (m5S) and hamster (Syrian hamster embryo (SHE)) cell lines were loaded on the Space Shuttle Discovery (STS-95 mission) and grown during a 9-daymission. After landing, the micronuclei resulting from abnormal nuclear division and accumulationof stress-responsive proteins such as p53 and mitogen-activated protein kinases (MAPKs), which are involved in radiation-induced signal transduction cascades, were analyzed. The frequencies of micronucleiin all the four mammalian cell strains tested were not significantly different between flight and ground control samples. Also, the cellular amounts of p53, p21 (WAF1/SDI1/CIP1) and activated (phosphorylated) forms of three distinct MAPKs in MCF7 and m5S cells of flight samples were similar to those of ground control samples. These results indicated that anyeffect of space radiation, microgravity, or combination of both were not detectable, at least under thepresent experimental conditions. (author)

  8. The Protein Arginine Methylase 5 (PRMT5/SKB1) Gene Is Required for the Maintenance of Root Stem Cells in Response to DNA Damage.

    Science.gov (United States)

    Li, Qiuling; Zhao, Yan; Yue, Minghui; Xue, Yongbiao; Bao, Shilai

    2016-04-20

    Plant root stem cells and their surrounding microenvironment, namely the stem cell niche, are hypersensitive to DNA damage. However, the molecular mechanisms that help maintain the genome stability of root stem cells remain elusive. Here we show that the root stem cells in the skb1 (Shk1 kinase binding protein 1) mutant undergoes DNA damage-induced cell death, which is enhanced when combined with a lesion of the Ataxia-telangiectasia mutated (ATM) or the ATM/RAD3-related (ATR) genes, suggesting that the SKB1 plays a synergistically effect with ATM and ATR in DNA damage pathway. We also provide evidence that SKB1 is required for the maintenance of quiescent center (QC), a root stem cell niche, under DNA damage treatments. Furthermore, we report decreased and ectopic expression of SHORTROOT (SHR) in response to DNA damage in the skb1 root tips, while the expression of SCARECROW (SCR) remains unaffected. Our results uncover a new mechanism of plant root stem cell maintenance under DNA damage conditions that requires SKB1. PMID:27090604

  9. In vitro metabolism study of normal and tumor cells when exposed to red LED light

    Science.gov (United States)

    Stolbovskaya, Olga V.; Khairullin, Radik M.; Saenko, Yuri V.; Krasnikova, Ekaterina S.; Krasnikov, Aleksandr V.; Fomin, Aleksandr A.; Skaptsov, Aleksandr A.

    2016-04-01

    This work presents the results of studying the mitochondrial membrane potential, intracellular ROS, peculiarities of the cell cycle of cancer cells HCT-116 and the normal line of CHO cells when exposed to the red LED light with a wavelength range of 0.620-0.680 μm. A dose-dependent increase in mitochondrial membrane potential and intracellular ROS concentration in cancer cells HCT-116 was established. In normal CHO cell line a dose-dependent reduction of mitochondrial membrane potential and dose-dependent increase in intracellular ROS occur. It has been shown that the sensitivity of the studied cell lines to the red light depends on the stage of the cell cycle.

  10. Protein C inhibitor (PCI binds to phosphatidylserine exposing cells with implications in the phagocytosis of apoptotic cells and activated platelets.

    Directory of Open Access Journals (Sweden)

    Daniela Rieger

    Full Text Available Protein C Inhibitor (PCI is a secreted serine protease inhibitor, belonging to the family of serpins. In addition to activated protein C PCI inactivates several other proteases of the coagulation and fibrinolytic systems, suggesting a regulatory role in hemostasis. Glycosaminoglycans and certain negatively charged phospholipids, like phosphatidylserine, bind to PCI and modulate its activity. Phosphatidylerine (PS is exposed on the surface of apoptotic cells and known as a phagocytosis marker. We hypothesized that PCI might bind to PS exposed on apoptotic cells and thereby influence their removal by phagocytosis. Using Jurkat T-lymphocytes and U937 myeloid cells, we show here that PCI binds to apoptotic cells to a similar extent at the same sites as Annexin V, but in a different manner as compared to live cells (defined spots on ∼10-30% of cells. PCI dose dependently decreased phagocytosis of apoptotic Jurkat cells by U937 macrophages. Moreover, the phagocytosis of PS exposing, activated platelets by human blood derived monocytes declined in the presence of PCI. In U937 cells the expression of PCI as well as the surface binding of PCI increased with time of phorbol ester treatment/macrophage differentiation. The results of this study suggest a role of PCI not only for the function and/or maturation of macrophages, but also as a negative regulator of apoptotic cell and activated platelets removal.

  11. 'Rogue' cells observed in children exposed to radiation from the Chernobyl accident

    Energy Technology Data Exchange (ETDEWEB)

    Sevan' kaev, A.V.; Tsyb, A.F.; Zhloba, A.A.; Moiseenko, V.V. (Russian Academy of Medical Science, Obninsk (Russian Federation). Medical Radiological Research Centre); Lloyd, D.C. (National Radiological Protection Board, Chilton (United Kingdom)); Skrjabin, A.M. (Scientific Research Inst. of Radiation Medicine, Gomel (Belarus)); Climov, V.M. (Special Regional Hospital, Gomel (Belarus). Public Health)

    1993-03-01

    Eight 'rogue' lymphocyte metaphases containing a large number of aberrant chromosomes were noted during a survey of chromosomal damage in 328 Belarussian children. The study population comprised children of families living in territory contaminated by radiation from the Chernobyl accident. The majority of the sample had been evacuated within 1 week from very heavily polluted territory to areas that had received much less fallout. Two hundred cells were scored per subject and one rogue cell was found in a child exposed in utero; one in a child conceived after the accident and six in the postnatally exposed group. The possibility that the damage was due to exposure to radio-iodine concentrated in the thyroid gland, or to radiation from incorporated hot particles' of an alpha or beta/gamma emitter is discussed. It is concluded that the damage to these cells is unlikely to have been caused by radiation. (Author).

  12. Cytotoxic mechanism related to dihydrolipoamide dehydrogenase in Leydig cells exposed to heavy metals

    International Nuclear Information System (INIS)

    Heavy metals are common environmental toxicants with adverse effects on steroid biosynthesis. The importance of mitochondria has been recognized in cytotoxic mechanism of heavy metals on Leydig cells these years. But it is still poorly known. Our previous study reported that dihydrolipoamide dehydrogenase (DLD) located on the mitochondria was significantly decreased in Leydig cells exposed to cadmium, which suggested that DLD might be involved in the cytotoxic effects. Therefore, the altered expression of DLD was validated in rats and R2C cells exposed to cadmium, manganese and lead, and the role of DLD in the steroid synthesis pathway cAMP/PKA-ERK1/2 was investigated in this study. With a low expression of DLD, heavy metals dramatically reduced the levels of steroid hormone by inhibiting the activation of cAMP/PKA, PKC signaling pathway and the steroidogenic enzymes StAR, CYP11A1 and 3β-HSD. After knockdown of DLD in R2C cells, progesterone synthesis was reduced by 40%, and the intracellular concentration of cAMP, protein expression of StAR, 3β-HSD, PKA, and the phosphorylation of ERK1/2 were also decreased. These results highlight that DLD is down-regulation and related to steroid biosynthesis in Leyig cells exposed to heavy metals; cAMP/PKA act as downstream effector molecules of DLD, which activate phosphorylation of ERK1/2 to initiate the steroidogenesis

  13. Increased frequency of micronucleated exfoliated cells among humans exposed in vivo to mobile telephone radiations

    International Nuclear Information System (INIS)

    Complete text of publication follows. The health concerns have been raised following the enormous increase in the use of wireless mobile telephones through out the world. This investigation had been taken, with the motive to find out whether mobile phone radiations cause any in vivo effects on the frequency of micronucleated exfoliated cells in the exposed subjects. A total of 109 subjects including 85 regular mobile phone users (exposed) and 24 non-users (controls) had participated in this study. Exfoliated cells were obtained by swabbing the buccal-mucosa from exposed as well as sex-age-matched controls. One thousand exfoliated cells were screened from each individual for nuclear anomalies including micronuclei (MN), karyolysis (KL), karyorrhexis (KH), broken egg (BE) and bi-nucleated (BN) cells. The average daily duration of exposure to mobile phone radiations is 61.26 minutes with an overall average duration of exposure in term of years is 2.35 years in exposed subjects along with the 9.84±0.745 MNC (micronucleated cells) and 10.72±0.889 TMN (total micronuclei) as compared to zero duration of exposure along with average 3.75±0.774 MNC and 4.00±0.808 TMN in controls. The means are significantly different in case MNC and TMN at 0.01% level of significance. For all other nuclear anomalies (KL, KH, BE and BN cells) the means are found statistically nonsignificant. A positive correlation was found in the frequency of MNC and TMN with respect to duration of exposure time.

  14. The Vitamin A Derivative All-Trans Retinoic Acid Repairs Amyloid-β-Induced Double-Strand Breaks in Neural Cells and in the Murine Neocortex

    Directory of Open Access Journals (Sweden)

    Emmanuelle Gruz-Gibelli

    2016-01-01

    Full Text Available The amyloid-β peptide or Aβ is the key player in the amyloid-cascade hypothesis of Alzheimer’s disease. Aβ appears to trigger cell death but also production of double-strand breaks (DSBs in aging and Alzheimer’s disease. All-trans retinoic acid (RA, a derivative of vitamin A, was already known for its neuroprotective effects against the amyloid cascade. It diminishes, for instance, the production of Aβ peptides and their oligomerisation. In the present work we investigated the possible implication of RA receptor (RAR in repair of Aβ-induced DSBs. We demonstrated that RA, as well as RAR agonist Am80, but not AGN 193109 antagonist, repair Aβ-induced DSBs in SH-SY5Y cells and an astrocytic cell line as well as in the murine cortical tissue of young and aged mice. The nonhomologous end joining pathway and the Ataxia Telangiectasia Mutated kinase were shown to be involved in RA-mediated DSBs repair in the SH-SY5Y cells. Our data suggest that RA, besides increasing cell viability in the cortex of young and even of aged mice, might also result in targeted DNA repair of genes important for cell or synaptic maintenance. This phenomenon would remain functional up to a point when Aβ increase and RA decrease probably lead to a pathological state.

  15. Non-homologous end joining pathway is the major route of protection against 4β-hydroxywithanolide E-induced DNA damage in MCF-7 cells.

    Science.gov (United States)

    You, B-J; Wu, Y-C; Lee, C-L; Lee, H-Z

    2014-03-01

    4β-Hydroxywithanolide E is a bioactive withanolide extracted from Physalis peruviana. 4β-Hydroxywithanolide E caused reactive oxygen species production and cell apoptosis in human breast cancer MCF-7 cells. We further found that 4β-hydroxywithanolide E induced DNA damage and regulated the DNA damage signaling in MCF-7 cells. The DNA damage sensors and repair proteins act promptly to remove DNA lesions by 4β-hydroxywithanolide E. The ataxia-telangiectasia mutated protein (ATM)-dependent DNA damage signaling pathway is involved in 4β-hydroxywithanolide E-induced apoptosis of MCF-7 cells. Non-homologous end joining pathway, but not homologous recombination, is the major route of protection of MCF-7 cells against 4β-hydroxywithanolide E-induced DNA damage. 4β-Hydroxywithanolide E had no significant impact on the base excision repair pathway. In this study, we examined the 4β-hydroxywithanolide E-induced DNA damage as a research tool in project investigating the DNA repair signaling in breast cancer cells. We also suggest that 4β-hydroxywithanolide E assert its anti-tumor activity in carcinogenic progression and develop into a dietary chemopreventive agent. PMID:24373828

  16. Genetic recombination of Herpes simplex virus, the role of the host cell and UV-irradiation of the virus

    International Nuclear Information System (INIS)

    Recombination frequencies for two sets of genetic markers of Herpes simplex virus were determined in various host cells with and without ultraviolet irradiation of the virus. UV irradiation increased the recombination frequency in all the cell types studied in direct proportion to the unrepaired lethal damage. In human skin fibroblasts derived from a patient with xeroderma pigmentosum (XP) of complementation group A, a given dose of UV stimulated recombination more than that in fibroblasts from normal individuals. On the other hand, UV stimulation of HSV recombination was slightly less than normal in fibroblasts derived from a patient with a variant form XP and from an ataxia telangiectasia patient. Caffeine, an agent known to inhibit repair of UV damage, reduced recombination in most of the cell types studied but did not suppress the UV-induced increase in recombination. These findings suggest that for virus DNA with the same number of unrepaired UV-lesions, each of the tested cell types promoted HSV-recombination to an equivalent extent. (orig.)

  17. Similarities between human ataxia fibroblasts and murine SCID cells: high sensitivity to γ rays and high frequency of methotrexate-induced DHFR gene amplification, but normal radiosensitivity to densely ionizing α particles

    International Nuclear Information System (INIS)

    Two γ-ray hypersensitive cell lines, human ataxia telangiectasia (AT) and murine severe combined immune deficiency (SCID) cells, proved to be very competent in amplifying their dihydrofolate reductase (DHFR) gene under methotrexate selection stress. Over a period of months, methotrexate-resistant clones were obtained which were able to grow in progressively increasing methotrexate concentrations up to 1 mM. By then methotrexate-resistant AT and SCID cells had amplified their DHFR gene 6- and 30-fold, respectively, and showed very high DHFR mRNA expression. In contrast, related cells with normal radiosensitivity (human GM637 and mouse BALB/c fibroblasts) did not show DHFR gene amplification under comparable conditions. This correlation of the capacity of DHFR gene amplification and γ-ray hypersensitivity in AT and SCID cells suggests that gene amplification may have a mechanism(s) in common with those involved in repair of γ-radiation-induced damage. No difference in cell killing could be observed following exposure to densely ionizing α particles: AT and SCID cells exhibited comparable survival rates to GM637 and BALB/c cells, respectively. (orig.)

  18. Similarities between human ataxia fibroblasts and murine SCID cells: high sensitivity to [gamma] rays and high frequency of methotrexate-induced DHFR gene amplification, but normal radiosensitivity to densely ionizing [alpha] particles

    Energy Technology Data Exchange (ETDEWEB)

    Luecke-Huhle, C. (Kernforschungszentrum Karlsruhe, Inst. fuer Genetik (Germany))

    1994-07-01

    Two [gamma]-ray hypersensitive cell lines, human ataxia telangiectasia (AT) and murine severe combined immune deficiency (SCID) cells, proved to be very competent in amplifying their dihydrofolate reductase (DHFR) gene under methotrexate selection stress. Over a period of months, methotrexate-resistant clones were obtained which were able to grow in progressively increasing methotrexate concentrations up to 1 mM. By then methotrexate-resistant AT and SCID cells had amplified their DHFR gene 6- and 30-fold, respectively, and showed very high DHFR mRNA expression. In contrast, related cells with normal radiosensitivity (human GM637 and mouse BALB/c fibroblasts) did not show DHFR gene amplification under comparable conditions. This correlation of the capacity of DHFR gene amplification and [gamma]-ray hypersensitivity in AT and SCID cells suggests that gene amplification may have a mechanism(s) in common with those involved in repair of [gamma]-radiation-induced damage. No difference in cell killing could be observed following exposure to densely ionizing [alpha] particles: AT and SCID cells exhibited comparable survival rates to GM637 and BALB/c cells, respectively. (orig.)

  19. The Secretome of Human Bronchial Epithelial Cells Exposed to Fine Atmospheric Particles Induces Fibroblast Proliferation

    Directory of Open Access Journals (Sweden)

    Laurent Martinon

    2013-08-01

    Full Text Available Chronic exposure to particulate pollution is suspected to exacerbate inflammatory respiratory diseases such as asthma characterized by an airway remodelling involving fibrosis. Our study aims to investigate whether the secretome from human bronchial epithelial (HBE cells exposed to fine particulate matter (PM induces fibroblast proliferation. Primary HBE cells grown on air liquid interface were repeatedly exposed to fine PM at 5 and 10 µg/cm² (four treatments, 48 hours apart and maintained in culture for five weeks. Collected basolateral culture medium was used as a conditioned medium for the subsequent treatment of fibroblasts. We observed that the conditioned medium collected from HBE cells treated with fine PM increased the growth rate of fibroblasts compared to the conditioned medium collected from control HBE cells. Fibroblast phenotype assessed by the observation of the vimentin network was well preserved. The mitogenic effect of conditioned medium was reduced in the presence of anti-epidermal growth factor receptor (EGFR, anti-amphiregulin or anti-TGFa, underlining the role of EGFR ligands in fibroblast proliferation. When fibroblasts were co-cultured with HBE cells treated once with fine PM, they exhibited a higher growth rate than fibroblasts co-cultured with non-treated HBE cells. Altogether these data show that the exposure of HBE cells to fine PM induced the production of EGFR ligands in sufficient amount to stimulate fibroblast proliferation providing insight into the role of PM in airway remodelling.

  20. ATM/ATR-related checkpoint signals mediate arsenite-induced G{sub 2}/M arrest in primary aortic endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Tsou, Tsui-Chun; Tsai, Feng-Yuan; Yeh, Szu-Ching; Chang, Louis W. [National Health Research Institutes, Division of Environmental Health and Occupational Medicine, Miaoli County (Taiwan)

    2006-12-15

    Epidemiological studies have demonstrated a high association of inorganic arsenic exposure with vascular disease. Our recent in vitro studies have linked this vascular damage to vascular endothelial dysfunction induced by arsenic exposure. However, cell-cycle arrest induced by arsenic and its involvement in vascular dysfunction remain to be clarified. In this study, we employed primary porcine aortic endothelial cells to investigate regulatory mechanisms of G{sub 2}/M phase arrest induced by arsenite. Our study revealed that lower concentrations of arsenite (1 and 3 {mu}M) increased cell proliferation, whereas higher concentrations of arsenite (10, 20, and 30 {mu}M) inhibited cell proliferation together with correlated increases in G{sub 2}/M phase arrest. We found that this arsenite-induced G{sub 2}/M phase arrest was accompanied by accumulation and/or phosphorylation of checkpoint-related molecules, including p53, Cdc25B, Cdc25C, and securin. Inhibition of activations of these checkpoint-related molecules by caffeine significantly attenuated the 30-{mu}M arsenite-induced G{sub 2}/M phase arrest by 93%. Our data suggest that the DNA damage responsive kinases ATM (ataxia-telangiectasia mutated) and ATR (ATM and Rad3-related) play critical roles in arsenite-induced G{sub 2}/M phase arrest in aortic endothelial cells possibly via regulation of checkpoint-related signaling molecules including p53, Cdc25B, Cdc25C, and securin. (orig.)

  1. DNA DAMAGE IN BUCCAL EPITHELIAL CELLS FROM INDIVIDUALS CHRONICALLY EXPOSED TO ARSENIC VIA DRINKING WATER IN INNER MONGOLIA, CHINA

    Science.gov (United States)

    The purpose of this pilot study was to assess DNA damage in buccal cells from individuals chronically exposed to arsenic via drinking water in Ba Men, Inner Mongolia. Buccal cells were collected from 19 Ba Men residents exposed to arsenic at 527.5 ? 23.7 g/L (mean ? SEM) and ...

  2. Phospholipidomic Profile Variation on THP-1 Cells Exposed to Skin or Respiratory Sensitizers and Respiratory Irritant.

    Science.gov (United States)

    Martins, João D; Maciel, Elisabete A; Silva, Ana; Ferreira, Isabel; Ricardo, Fernando; Domingues, Pedro; Neves, Bruno M; Domingues, Maria Rosário M; Cruz, Maria Teresa

    2016-12-01

    Occupational exposure to low molecular weight reactive chemicals often leads to development of allergic reactions such as allergic contact dermatitis and respiratory allergies. Further insights into the interaction of these chemicals with physiopathological relevant cellular models might provide the foundations for novel non-animal approaches to safety assessment. In this work we used the human THP-1 cell line to determine phospholipidome changes induced by the skin sensitizer 1-fluoro-2,4-dinitrobenzene (DNFB), the respiratory allergen hexamethylene diisocyanate (HDI), and the irritant methyl salicylate (MESA). We detected that these chemicals differently induce lipid peroxidation and modulate THP-1 IL-1β, IL-12B, IL-8, CD86, and HMOX1 transcription. Decreased phosphatidylethanolamine content was detected in cells exposed to MESA, while profound alterations in the relative abundance of cardiolipin species were observed in cells exposed to DNFB. All chemicals tested induced a decrease in the relative abundance of plasmanyl phosphatidylcholine species PC (O-16:0e/18:1) and phosphatidylinositol species PI (34:1), while increasing PI (38:4). An increased abundance of oleic acid was observed in the phospholipids of cells exposed to DNFB while a decreased abundance of palmitic acid was detected in cells treated with MESA or DNFB. We conclude that both specific and common alterations at phospholipidome levels are triggered by the different chemicals, while not allowing a complete distinction between them using a Canonical Analysis of Principal Coordinates (CAP). The common effects observed at phospholipids level with all the chemicals tested might be related to unspecific cell cytotoxic mechanisms that nevertheless may contribute to the elicitation of specific immune responses. J. Cell. Physiol. 231: 2639-2651, 2016. © 2016 Wiley Periodicals, Inc. PMID:26946329

  3. Apoptosis and necroptosis are induced in rainbow trout cell lines exposed to cadmium.

    Science.gov (United States)

    Krumschnabel, Gerhard; Ebner, Hannes L; Hess, Michael W; Villunger, Andreas

    2010-08-01

    Cadmium is an important environmental toxicant that can kill cells. A number of studies have implicated apoptosis as well as necrosis and, most recently, a form of programmed necrosis termed necroptosis in the process of cadmium-mediated toxicity, but the exact mechanism remains ill-defined and may depend on the affected cell type. This study investigated which mode of cell death may be responsible for cell death induction in cadmium-exposed trout cell lines from gill and liver and if this cell death was sensitive to inhibitors of necroptosis or apoptosis, respectively. It was observed that intermediate levels of cadmium that killed approximately 50% of the cells over 96-120h of exposure caused cell death that morphologically resembled apoptosis and was associated with an increase of apoptotic markers such as the number of cells with diminished DNA content (sub-G1 cells), condensed or fragmented nuclei, and elevation of caspase-3 activity. At the same time, however, cells also lost plasma membrane integrity, as indicated by uptake of propidium iodide, showed a decrease of ATP levels and mitochondrial membrane potential, and displayed cell swelling, signs associated with secondary necrosis, or equally possible, necroptotic cell death. Importantly, many of these alterations were at least partly inhibited by the necroptosis inhibitor necrostatin-1 and were to a lesser extent also sensitive to the pan-caspase inhibitor zVAD-fmk, indicating that multiple modes of cell death are concurrently induced in cadmium-exposed trout cells, including necroptosis and apoptosis. Cell death appeared to lack concurrent radical formation, consistent with genetically regulated necroptotic cell death, but was characterized by the rapid induction of DNA damage markers, and the early onset of disintegration of the Golgi complex. Comparative experiments evaluating copper-toxicity indicated that in comparison to cadmium much higher concentrations of this metal were required to induce cell

  4. Apoptosis and necroptosis are induced in rainbow trout cell lines exposed to cadmium

    International Nuclear Information System (INIS)

    Cadmium is an important environmental toxicant that can kill cells. A number of studies have implicated apoptosis as well as necrosis and, most recently, a form of programmed necrosis termed necroptosis in the process of cadmium-mediated toxicity, but the exact mechanism remains ill-defined and may depend on the affected cell type. This study investigated which mode of cell death may be responsible for cell death induction in cadmium-exposed trout cell lines from gill and liver and if this cell death was sensitive to inhibitors of necroptosis or apoptosis, respectively. It was observed that intermediate levels of cadmium that killed approximately 50% of the cells over 96-120 h of exposure caused cell death that morphologically resembled apoptosis and was associated with an increase of apoptotic markers such as the number of cells with diminished DNA content (sub-G1 cells), condensed or fragmented nuclei, and elevation of caspase-3 activity. At the same time, however, cells also lost plasma membrane integrity, as indicated by uptake of propidium iodide, showed a decrease of ATP levels and mitochondrial membrane potential, and displayed cell swelling, signs associated with secondary necrosis, or equally possible, necroptotic cell death. Importantly, many of these alterations were at least partly inhibited by the necroptosis inhibitor necrostatin-1 and were to a lesser extent also sensitive to the pan-caspase inhibitor zVAD-fmk, indicating that multiple modes of cell death are concurrently induced in cadmium-exposed trout cells, including necroptosis and apoptosis. Cell death appeared to lack concurrent radical formation, consistent with genetically regulated necroptotic cell death, but was characterized by the rapid induction of DNA damage markers, and the early onset of disintegration of the Golgi complex. Comparative experiments evaluating copper-toxicity indicated that in comparison to cadmium much higher concentrations of this metal were required to induce cell

  5. Apoptosis and necroptosis are induced in rainbow trout cell lines exposed to cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Krumschnabel, Gerhard, E-mail: Gerhard.Krumschnabel@i-med.ac.at [Division of Developmental Immunology, Biocenter, Medical University Innsbruck, Fritz-Preglstr. 3, Innsbruck (Austria); Ebner, Hannes L.; Hess, Michael W. [Division of Histology and Embryology, Medical University Innsbruck, Innsbruck (Austria); Villunger, Andreas [Division of Developmental Immunology, Biocenter, Medical University Innsbruck, Fritz-Preglstr. 3, Innsbruck (Austria)

    2010-08-01

    Cadmium is an important environmental toxicant that can kill cells. A number of studies have implicated apoptosis as well as necrosis and, most recently, a form of programmed necrosis termed necroptosis in the process of cadmium-mediated toxicity, but the exact mechanism remains ill-defined and may depend on the affected cell type. This study investigated which mode of cell death may be responsible for cell death induction in cadmium-exposed trout cell lines from gill and liver and if this cell death was sensitive to inhibitors of necroptosis or apoptosis, respectively. It was observed that intermediate levels of cadmium that killed approximately 50% of the cells over 96-120 h of exposure caused cell death that morphologically resembled apoptosis and was associated with an increase of apoptotic markers such as the number of cells with diminished DNA content (sub-G1 cells), condensed or fragmented nuclei, and elevation of caspase-3 activity. At the same time, however, cells also lost plasma membrane integrity, as indicated by uptake of propidium iodide, showed a decrease of ATP levels and mitochondrial membrane potential, and displayed cell swelling, signs associated with secondary necrosis, or equally possible, necroptotic cell death. Importantly, many of these alterations were at least partly inhibited by the necroptosis inhibitor necrostatin-1 and were to a lesser extent also sensitive to the pan-caspase inhibitor zVAD-fmk, indicating that multiple modes of cell death are concurrently induced in cadmium-exposed trout cells, including necroptosis and apoptosis. Cell death appeared to lack concurrent radical formation, consistent with genetically regulated necroptotic cell death, but was characterized by the rapid induction of DNA damage markers, and the early onset of disintegration of the Golgi complex. Comparative experiments evaluating copper-toxicity indicated that in comparison to cadmium much higher concentrations of this metal were required to induce cell

  6. Comparison between half-cell potential of reinforced concrete exposed to carbon dioxide and chloride environment

    OpenAIRE

    Somnuk Tangtermsirikul; Waree Kongprawechnon; Kitipoom Chansuriyasak; Chalermchai Wanichlamlart

    2010-01-01

    The objective of this study is to investigate the effect of concrete mix proportion and fly ash on half-cell potential (HCP)and corrosion current density (icorr) of steel in concrete exposed to different environments. Reinforced concrete specimenswith different fly ash replacement percentages and water to binder ratios (w/b) were studied in this paper. The specimenswere subjected to two highly corrosive environments which are chloride and carbon dioxide. HCP and icorr were used tomonitor the ...

  7. High content image analysis for human H4 neuroglioma cells exposed to CuO nanoparticles

    OpenAIRE

    Ma Jinwen; Zhu Jinmin; Zhou Xiaobo; Li Fuhai; Huang Xudong; Wong Stephen TC

    2007-01-01

    Abstract Background High content screening (HCS)-based image analysis is becoming an important and widely used research tool. Capitalizing this technology, ample cellular information can be extracted from the high content cellular images. In this study, an automated, reliable and quantitative cellular image analysis system developed in house has been employed to quantify the toxic responses of human H4 neuroglioma cells exposed to metal oxide nanoparticles. This system has been proved to be a...

  8. Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

    Institute of Scientific and Technical Information of China (English)

    刘建国; 张晓丽; 孙延红; 林伟

    2010-01-01

    The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD),peroxidase (POD),catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O2ˉ).The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H.pluvialis during exposure to reactive oxygen species (ROS) such as Oˉ2.Astaxanthin reacte...

  9. Frequency patterns of T-cell exposed motifs in immunoglobulin heavy chain peptides presented by MHCs

    Directory of Open Access Journals (Sweden)

    Robert D. Bremel

    2014-10-01

    Full Text Available Immunoglobulins are highly diverse protein sequences that are processed and presented to T-cells by B-cells and other antigen presenting cells. We examined a large dataset of immunoglobulin heavy chain variable regions (IGHV to assess the diversity of T-cell exposed motifs (TCEM. TCEM comprise those amino acids in a MHC-bound peptide which face outwards, surrounded by the MHC histotope, and which engage the T-cell receptor. Within IGHV there is a distinct pattern of predicted MHC class II binding and a very high frequency of re-use of the TCEMs. The re-use frequency indicates that only a limited number of different cognate T-cells are required to engage many different clonal B-cells. The amino acids in each outward-facing TCEM are intercalated with the amino acids of inward-facing MHC groove-exposed motifs (GEM. Different GEM may have differing, allele-specific, MHC binding affinities. The intercalation of TCEM and GEM in a peptide allows for a vast combinatorial repertoire of epitopes, each eliciting a different response. Outcome of T-cell receptor binding is determined by overall signal strength, which is a function of the number of responding T-cells and the duration of engagement. Hence, the frequency of T-cell exposed motif re-use appears to be an important determinant of whether a T-cell response is stimulatory or suppressive. The frequency distribution of TCEMs implies that somatic hypermutation is followed by clonal expansion that develop along repeated pathways. The observations of TCEM and GEM derived from immunoglobulins suggest a relatively simple, yet powerful, mechanism to correlate T-cell polyspecificity, through re-use of TCEMs, with a very high degree of specificity achieved by combination with a diversity of GEMs. The frequency profile of TCEMs also points to an economical mechanism for maintaining T-cell memory, recall, and self-discrimination based on an endogenously generated profile of motifs.

  10. High content image analysis for human H4 neuroglioma cells exposed to CuO nanoparticles

    Directory of Open Access Journals (Sweden)

    Ma Jinwen

    2007-10-01

    Full Text Available Abstract Background High content screening (HCS-based image analysis is becoming an important and widely used research tool. Capitalizing this technology, ample cellular information can be extracted from the high content cellular images. In this study, an automated, reliable and quantitative cellular image analysis system developed in house has been employed to quantify the toxic responses of human H4 neuroglioma cells exposed to metal oxide nanoparticles. This system has been proved to be an essential tool in our study. Results The cellular images of H4 neuroglioma cells exposed to different concentrations of CuO nanoparticles were sampled using IN Cell Analyzer 1000. A fully automated cellular image analysis system has been developed to perform the image analysis for cell viability. A multiple adaptive thresholding method was used to classify the pixels of the nuclei image into three classes: bright nuclei, dark nuclei, and background. During the development of our image analysis methodology, we have achieved the followings: (1 The Gaussian filtering with proper scale has been applied to the cellular images for generation of a local intensity maximum inside each nucleus; (2 a novel local intensity maxima detection method based on the gradient vector field has been established; and (3 a statistical model based splitting method was proposed to overcome the under segmentation problem. Computational results indicate that 95.9% nuclei can be detected and segmented correctly by the proposed image analysis system. Conclusion The proposed automated image analysis system can effectively segment the images of human H4 neuroglioma cells exposed to CuO nanoparticles. The computational results confirmed our biological finding that human H4 neuroglioma cells had a dose-dependent toxic response to the insult of CuO nanoparticles.

  11. Sensitivity of morphological change of Vero cells exposed to lipophilic compounds and its mechanism

    International Nuclear Information System (INIS)

    To find a sensitive cytotoxic response to reflect the toxicity of trace organic pollutants, the sensitivity and reliability of morphological change and proliferation inhibition of Vero cells exposed to lipophilic compounds and the leachate from products related to drinking water (PRDW) were compared, and the mechanism of the morphological change in Vero cells was studied. Results showed the proportion of morphologically changed cells increased with increasing 2,4,6-trichlorophenol (TCP)/perfluorooctane sulfonate (PFOS) concentration. However, at low TCP concentrations, inhibition of cell proliferation did not correlate to TCP concentration. After exposure to the leachate from PRDW extracted at different temperatures, the percentage of morphologically changed cells increased with extracting temperature, but the inhibition of cell proliferation failed to reflect the correlation to extracting temperature. These imply cell morphological change is a more sensitive and reliable method to reflect toxicity of trace organic pollutants than proliferation inhibition. Flow cytometry analysis indicated cell membrane damage was an early and sensitive cytotoxic response comparing with necrosis, resulting in cell morphological change, which may be due to the interference of lipophilic compounds. Lipophilic compound accumulated in cell membrane to interfere the assembly process of membrane protein and phospholipid.

  12. Effects of selenocystine on lead-exposed Chinese hamster ovary (CHO) and PC-12 cells

    International Nuclear Information System (INIS)

    Lead is a pervasive environmental toxin that affects multiple organ systems, including the nervous, renal, reproductive, and hematological systems. Even though it is probably the most studied toxic metal, some of the symptoms of lead toxicity still cannot be explained by known molecular mechanisms. Therefore, lead-induced oxidative stress has recently started to gain attention. This in vitro study confirms the existence of oxidative stress due to lead exposure. Administration of lead acetate (PbA) to cultures of Chinese hamster ovary cells (CHO) had a concentration-dependent inhibitory effect on colony formation and cell proliferation. This inhibition was eliminated by 5 μM selenocystine (SeCys). In order to evaluate the nature of SeCys's effect, we measured glutathione (GSH), its oxidized form glutathione disulfide (GSSG), malondialdehyde (MDA), catalase, and GSH peroxidase (GPx) activities in lead-exposed CHO cells both in the presence and absence of SeCys. Increases in MDA, catalase, and GPx activities were observed in cultures that received only PbA, but supplementation with SeCys returned these measures to pretreatment levels. The ratio of GSH to GSSG increased in lead-exposed cells incubated in SeCys-enhanced media but declined in cultures treated with PbA only. In order to determine whether SeCys also reverses lead-induced neurotoxicity, a neuronal cell line, PC-12 cells, was used. Lead's inhibition on neurite formation was significantly eliminated by SeCys in PC-12 cells. Our results suggest that SeCys can confer protection against lead-induced toxicity in CHO cells and neurotoxicity in PC-12 cells

  13. Diagnostic and pathogenetic role of café-au-lait macules in nevoid basal cell carcinoma syndrome.

    Science.gov (United States)

    Ponti, Giovanni; Tomasi, Aldo; Pastorino, Lorenza; Ruini, Cristel; Guarneri, Carmelo; Mandel, Victor Desmond; Seidenari, Stefania; Pellacani, Giovanni

    2012-01-01

    Café au lait spots (CALS) are common dermatologic findings that can at the same time arise in a variety of pathologic conditions such as Neurofibromatosis type 1 (NF1), together with numerous hereditary syndromes for which they represent either diagnostic criteria or associated elements (McCune Albright, Silver-Russell, LEOPARD, Ataxia-Telangiectasia). A review of the literature also revealed two cases of association with NBCCS. We report here the case of a female proband with CALS associated to Nevoid Basal Cell Carcinoma Syndrome (NBCCS) with known PTCH1 germline mutation (C.1348-2A>G) who had been misdiagnosed with NF1 in her childhood because of 5 CALS and cutaneous nodules. The patient presented a giant cell tumor of the skin, palmar and calcaneal epidermoidal cystic nodules, odontogenic keratocystic tumors and deformity of the jaw profile. Her family history brought both her brother and father to our attention because of the presence of KCOTs diagnosed at early age: after genetic testing, the same PTCH1 germline mutation was identified in the three family members. Clinical criteria are used for discerning NF1 diagnosis (size, number and onset age), while there are no definite guidelines concerning CALS except for their presence. In our experience, we have noted an association of CALS with NBCCS; this seems interesting because we already know clinical criteria are a dynamic entity and can be modified by epidemiologic evidences. PMID:23107377

  14. Diagnostic and pathogenetic role of café-au-lait macules in nevoid basal cell carcinoma syndrome

    Directory of Open Access Journals (Sweden)

    Ponti Giovanni

    2012-10-01

    Full Text Available Abstract Café au lait spots (CALS are common dermatologic findings that can at the same time arise in a variety of pathologic conditions such as Neurofibromatosis type 1 (NF1, together with numerous hereditary syndromes for which they represent either diagnostic criteria or associated elements (McCune Albright, Silver-Russell, LEOPARD, Ataxia-Telangiectasia. A review of the literature also revealed two cases of association with NBCCS. We report here the case of a female proband with CALS associated to Nevoid Basal Cell Carcinoma Syndrome (NBCCS with known PTCH1 germline mutation (C.1348-2A>G who had been misdiagnosed with NF1 in her childhood because of 5 CALS and cutaneous nodules. The patient presented a giant cell tumor of the skin, palmar and calcaneal epidermoidal cystic nodules, odontogenic keratocystic tumors and deformity of the jaw profile. Her family history brought both her brother and father to our attention because of the presence of KCOTs diagnosed at early age: after genetic testing, the same PTCH1 germline mutation was identified in the three family members. Clinical criteria are used for discerning NF1 diagnosis (size, number and onset age, while there are no definite guidelines concerning CALS except for their presence. In our experience, we have noted an association of CALS with NBCCS; this seems interesting because we already know clinical criteria are a dynamic entity and can be modified by epidemiologic evidences.

  15. Cisplatin-mediated radiosensitization of non-small cell lung cancer cells is stimulated by ATM inhibition

    International Nuclear Information System (INIS)

    Background and purpose: Cisplatin activates ataxia-telangiectasia-mutated (ATM), a protein with roles in DNA repair, cell cycle progression and autophagy. We investigated the radiosensitizing effect of cisplatin with respect to its effect on ATM pathway activation. Material and methods: Non-small cell lung cancer cells (NSCLC) cell lines (A549, H460) and human fibroblast (ATM-deficient AT5, ATM-proficient 1BR3) cells were used. The effects of cisplatin combined with irradiation on ATM pathway activity, clonogenicity, DNA double-strand break (DNA-DSB) repair and cell cycle progression were analyzed with Western blotting, colony formation and γ-H2AX foci assays as well as FACS analysis, respectively. Results: Cisplatin radiosensitized H460 cells, but not A549 cells. Radiosensitization of H460 cells was not due to impaired DNA-DSB repair, increased apoptosis or cell cycle dysregulation. The lack of radiosensitization demonstrated for A549 cells was associated with cisplatin-mediated stimulation of ATM (S1981) and AMPKα (T172) phosphorylation and autophagy. However, in both cell lines inhibition of ATM and autophagy by KU-55933 and chloroquine diphosphate (CQ) respectively resulted in a significant radiosensitization. Combined treatment with the AMPK inhibitor compound-C led to radiosensitization of A549 but not of H460 cells. As compared to the treatment with KU-55933 alone, radiosensitivity of A549 cells was markedly stimulated by the combination of KU-55933 and cisplatin. However, the combination of CQ and cisplatin did not modulate the pattern of radiation sensitivity of A549 or H460 cells. In accordance with the results that cisplatin via stimulation of ATM activity can abrogate its radiosensitizing effect, ATM deficient cells were significantly sensitized to ionizing radiation by cisplatin. Conclusion: The results obtained indicate that ATM targeting can potentiate cisplatin-induced radiosensitization

  16. Insights on cryoprotectant toxicity from gene expression profiling of endothelial cells exposed to ethylene glycol.

    Science.gov (United States)

    Cordeiro, Rui Martins; Stirling, Soren; Fahy, Gregory M; de Magalhães, João Pedro

    2015-12-01

    Cryopreservation consists of preserving living cells or tissues generally at -80 °C or below and has many current applications in cell and tissue banking, and future potential for organ banking. Cryoprotective agents such as ethylene glycol (EG) are required for successful cryopreservation of most living systems, but have toxic side effects whose mechanisms remain largely unknown. In this work, we investigated the mechanisms of toxicity of ethylene glycol in human umbilical vein endothelial cells (HUVECs) as a model of the vascular endothelium in perfused organs. Exposing cells to 60% v/v EG for 2 h at 4 °C resulted in only a slight decrease in subsequent cell growth, suggesting only modest toxicity of EG for this cell type. Gene expression analysis with whole genome microarrays revealed signatures indicative of a generalized stress response at 24 h after EG exposure and a trend toward partial recovery at 72 h. The observed changes involved signalling pathways, glycoproteins, and genes involved in extracellular and transmembrane functions, the latter suggesting potential effects of ethylene glycol on membranes. These results continue to develop a new paradigm for understanding cryoprotectant toxicity and reveal molecular signatures helpful for future experiments in more completely elucidating the toxic effects of ethylene glycol in vascular endothelial cells and other cell types. PMID:26471925

  17. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    Science.gov (United States)

    Yuan, Hengguang; Hu, Shanglian; Huang, Peng; Song, Hua; Wang, Kan; Ruan, Jing; He, Rong; Cui, Daxiang

    2011-12-01

    Herein we are the first to report that single-walled carbon nanotubes (SWCNTs) exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS) generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  18. Single Walled Carbon Nanotubes Exhibit Dual-Phase Regulation to Exposed Arabidopsis Mesophyll Cells

    Directory of Open Access Journals (Sweden)

    Huang Peng

    2011-01-01

    Full Text Available Abstract Herein we are the first to report that single-walled carbon nanotubes (SWCNTs exhibit dual-phase regulation to Arabidopsis mesophyll cells exposed to different concentration of SWCNTs. The mesophyll protoplasts were prepared by enzyme digestion, and incubated with 15, 25, 50, 100 μg/ml SWCNTs for 48 h, and then were observed by optical microscopy and transmission electron microscopy, the reactive oxygen species (ROS generation was measured. Partial protoplasts were stained with propidium iodide and 4'-6- diamidino-2-phenylindole, partial protoplasts were incubated with fluorescein isothiocyanate-labeled SWCNTs, and observed by fluorescence microscopy. Results showed that SWCNTs could traverse both the plant cell wall and cell membrane, with less than or equal to 50 μg/ml in the culture medium, SWCNTs stimulated plant cells to grow out trichome clusters on their surface, with more than 50 μg/ml SWCNTs in the culture medium, SWCNTs exhibited obvious toxic effects to the protoplasts such as increasing generation of ROS, inducing changes of protoplast morphology, changing green leaves into yellow, and inducing protoplast cells' necrosis and apoptosis. In conclusion, single walled carbon nanotubes can get through Arabidopsis mesophyll cell wall and membrane, and exhibit dose-dependent dual-phase regulation to Arabidopsis mesophyll protoplasts such as low dose stimulating cell growth, and high dose inducing cells' ROS generation, necrosis or apoptosis.

  19. Reproductive integrity of mammalian cells exposed to power frequency electromagnetic fields.

    Science.gov (United States)

    Livingston, G K; Witt, K L; Gandhi, O P; Chatterjee, I; Roti Roti, J L

    1991-01-01

    Human lymphocytes and Chinese hamster ovary (CHO) fibroblasts were analyzed for cytogenetic and cytotoxic endpoints to determine whether exposure to power frequency (60 Hz) electromagnetic fields (EMF) interferes with normal cell growth and reproduction. An exposure chamber was built to apply variable electric current densities of 3, 30, 300, and 3,000 microA/cm2, simultaneously with a fixed magnetic field of 2.2 G to proliferating cells. The current densities were chosen to bracket those that may be induced in the human body by fields measured beneath high voltage (765 kV) power transmission lines. The electric current was applied through the media of a cell culture chamber positioned between two stainless steel electrodes but separated from direct contact with the culture media by a salt bridge composed of a 1% agarose gel. The magnetic field was generated using two pairs of Helmholtz coils driven 73 degrees out of phase producing an elliptically polarized magnetic field 36 degrees out of phase with the electric field. The EMFs were measured and mapped inside the cell culture chamber to insure their uniformity. CHO cells were exposed continuously for 24-96 hr (depending on experiment) and human lymphocytes were exposed continuously for 72 hr. The EMFs were monitored throughout the entire treatment period using a multichannel chart recorder to verify continuous application of the desired fields. Sister-chromatid exchange and micronuclei were monitored to evaluate the potential for genotoxicity. In addition, standard growth curves, clonogenicity, and cell cycle kinetics were analyzed to evaluate possible cytotoxic effects. The experimental data consistently showed that the growth rate and reproductive integrity of both cell types was unaffected by exposure to the electromagnetic fields. PMID:1991460

  20. Nuclear respiratory factor 1 overexpression attenuates anti-benzopyrene‑7,8-diol-9,10-epoxide-induced S-phase arrest of bronchial epithelial cells.

    Science.gov (United States)

    Wu, Jing; Wang, Yaning; Wo, Da; Zhang, Lijuan; Li, Jue

    2016-05-01

    Nuclear respiratory factor 1 (NRF-1) has important roles in the regulation of several key metabolic genes required for cellular growth and respiration. A previous study by our group indicated that NRF‑1 is involved in mitochondrial dysfunction induced by the environmental pollutant benzo[a]pyrene in the 16HBE human bronchial epithelial cell line. In the present study, it was observed that its genotoxic metabolite, anti‑benzopyrene‑7,8‑diol‑9,10‑epoxide (BPDE), triggered cell cycle arrest in S‑phase in 16HBE cells by activating ataxia-telangiectasia (ATM)/checkpoint kinase (Chk)2 and ATM and Rad3 related (ATR)/Chk1 signaling pathways. NRF‑1 expression was suppressed by BPDE after treatment for 6 h. Flow cytometric analysis revealed that NRF‑1 overexpression attenuated cell cycle arrest in S‑phase induced by BPDE. In line with this result, DNA‑damage checkpoints were activated following NRF‑1 overexpression, as demonstrated by increased phosphorylation of ATM, Chk2 and γH2AX, but not ATR and Chk1, according to western blot analysis. It was therefore indicated that NRF‑1 overexpression attenuated BPDE‑induced S‑phase arrest via the ATM/Chk2 signaling pathway. PMID:27035420

  1. Live-cell imaging study of mitochondrial morphology in mammalian cells exposed to X-rays

    International Nuclear Information System (INIS)

    Morphological changes in mitochondria induced by X-irradiation in normal murine mammary gland cells were studied with a live-cell microscopic imaging technique. Mitochondria were visualised by staining with a specific fluorescent probe in the cells, which express fluorescent ubiquitination-based cell-cycle indicator 2 (Fucci2) probes to visualise cell cycle. In unirradiated cells, the number of cells with fragmented mitochondria was about 20 % of the total cells through observation period (96 h). In irradiated cells, the population with fragmented mitochondria significantly increased depending on the absorbed dose. Particularly, for 8 Gy irradiation, the accumulation of fragmentation persists even in the cells whose cell cycle came to a stand (80 % in G1 (G0-like) phase). The fraction reached to a maximum at 96 h after irradiation. The kinetics of the fraction with fragmented mitochondria was similar to that for cells in S/G2/M phase (20 %) through the observation period (120 h). The evidences show that, in irradiated cells, some signals are continually released from a nucleus or cytoplasm even in the G0-like cells to operate some sort of protein machineries involved in mitochondrial fission. It is inferred that this delayed mitochondrial fragmentation is strongly related to their dysfunction, and hence might modulate radiobiological effects such as mutation or cell death. (authors)

  2. γ-ray hypersensitivity and faulty DNA repair in cultured cells from humans exhibiting familial cancer proneness

    International Nuclear Information System (INIS)

    The most significant danger to irradiated individuals is the induction of cancer. Ataxia telangiectasia (AT) is known as a disorder linking radiosensitivity with cancer proneness, and AT is a rare inherited disorder. This is the degenerative multisystem affliction that is transmitted as a simple autosomal recessive trait. Cell culture studies disclosed the relationship between the cellular hypersensitivity to γ-ray inactivation in vitro and the propensity to develop cancer in vivo. The molecular evidence for the defects in the repair of radiogenic DNA damage has as yet been obtained only for AT, and it seems likely that anomalous DNA repair may not be the key causal factor in the development of some of the clinical abnormalities associated with the disease, including the tendency to develop lymphoproliferative cancer. Nevertheless, AT, Rothmund-Thomson syndrome (RTS), and acute myelogenous leukemia (AML) family show promise as the models for elucidating the importance of cellular radiosensitivity and imperfect DNA repair in the induction of cancer by radiation and radiomimetic carcinogens in the biosphere. Expanded efforts are required to identify heterozygosity for the AT genes in general population and to assess the role of the interaction between this genetic make-up and environmental carcinogens in the occurrence of common cancers. (Yamashita, S.)

  3. Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

    Science.gov (United States)

    Liu, Jianguo; Zhang, Xiaoli; Sun, Yanhong; Lin, Wei

    2010-01-01

    The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O{2/-}). The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H. pluvialis during exposure to reactive oxygen species (ROS) such as O{2/-}. Astaxanthin reacted with ROS much faster than did the protective enzymes, and had the strongest antioxidative capacity to protect against lipid peroxidation. The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells. Astaxanthin-enriched red cells had the strongest antioxidative capacity, followed by brown cells, and astaxanthin-deficient green cells. Although there was no significant increase in expression of protective enzymes, the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin, which quenched O{2/-} before the protective enzymes could act. In green cells, astaxanthin is very low or absent; therefore, scavenging of ROS is inevitably reliant on antioxidative enzymes. Accordingly, in green cells, these enzymes play the leading role in scavenging ROS, and the expression of these enzymes is rapidly increased to reduce excessive ROS. However, because ROS were constantly increased in this study, the enhance enzyme activity in the green cells was not able to repair the ROS damage, leading to elevated MDA content. Of the four defensive enzymes measured in astaxanthin-deficient green cells, SOD eliminates O{2/-}, POD eliminates H2O2, which is a by-product of SOD activity, and APX and CAT are then initiated to scavenge excessive ROS.

  4. Protein C Inhibitor (PCI) Binds to Phosphatidylserine Exposing Cells with Implications in the Phagocytosis of Apoptotic Cells and Activated Platelets

    OpenAIRE

    Daniela Rieger; Alice Assinger; Katrin Einfinger; Barbora Sokolikova; Margarethe Geiger

    2014-01-01

    Protein C Inhibitor (PCI) is a secreted serine protease inhibitor, belonging to the family of serpins. In addition to activated protein C PCI inactivates several other proteases of the coagulation and fibrinolytic systems, suggesting a regulatory role in hemostasis. Glycosaminoglycans and certain negatively charged phospholipids, like phosphatidylserine, bind to PCI and modulate its activity. Phosphatidylerine (PS) is exposed on the surface of apoptotic cells and known as a phagocytosis marke...

  5. Effects of Potassium Currents upon Action Potential of Cardiac Cells Exposed to External Electric fields

    Institute of Scientific and Technical Information of China (English)

    An-Ying Zhang; Xiao-Feng Pang

    2008-01-01

    Previous studies show that exposure to high-voltage electric fields would influence the electro cardiogram both in experimental animate and human beings. The effects of the external electric fields upon action potential of cardiac cells are studied in this paper based on the dynamical model, LR91. Fourth order Runger-Kuta is used to analyze the change of potassium ion channels exposed to external electric fields in detail. Results indicate that external electric fields could influence the current of potassium ion by adding an induced component voltage on membrane. This phenomenon might be one of the reasons of heart rate anomaly under the high-voltage electric fields.

  6. Colon stem cell and crypt dynamics exposed by cell lineage reconstruction.

    Directory of Open Access Journals (Sweden)

    Yitzhak Reizel

    2011-07-01

    Full Text Available Stem cell dynamics in vivo are often being studied by lineage tracing methods. Our laboratory has previously developed a retrospective method for reconstructing cell lineage trees from somatic mutations accumulated in microsatellites. This method was applied here to explore different aspects of stem cell dynamics in the mouse colon without the use of stem cell markers. We first demonstrated the reliability of our method for the study of stem cells by confirming previously established facts, and then we addressed open questions. Our findings confirmed that colon crypts are monoclonal and that, throughout adulthood, the process of monoclonal conversion plays a major role in the maintenance of crypts. The absence of immortal strand mechanism in crypts stem cells was validated by the age-dependent accumulation of microsatellite mutations. In addition, we confirmed the positive correlation between physical and lineage proximity of crypts, by showing that the colon is separated into small domains that share a common ancestor. We gained new data demonstrating that colon epithelium is clustered separately from hematopoietic and other cell types, indicating that the colon is constituted of few progenitors and ruling out significant renewal of colonic epithelium from hematopoietic cells during adulthood. Overall, our study demonstrates the reliability of cell lineage reconstruction for the study of stem cell dynamics, and it further addresses open questions in colon stem cells. In addition, this method can be applied to study stem cell dynamics in other systems.

  7. Radiation-Induced Bystander Effects in A549 Cells Exposed to 6 MV X-rays.

    Science.gov (United States)

    Yang, Shuning; Xu, Jing; Shao, Weixian; Geng, Chong; Li, Jia; Guo, Feng; Miao, Hui; Shen, Wenbin; Ye, Tao; Liu, Yazhou; Xu, Haiting; Zhang, Xuguang

    2015-07-01

    The aim of the study is to explore the bystander effects in A549 cells that have been exposed to 6MV X-ray. Control group, irradiated group, irradiated conditioned medium (ICM)-received group, and fresh medium group were designed in this study. A549 cells in the logarithmic growth phase were irradiated with 6MV X-ray at 0, 0.5, 1, 1.5, and 2. In ICM-received group, post-irradiation A549 cells were cultured for 3 h and were transferred into non-irradiated A549 cells for further cultivation. Clone forming test was applied to detect the survival fraction of cells. Annexin V-FITC/PI double-staining assay was used to detect the apoptosis of A549 cells 24, 48, 72, and 96 h after 2-Gy 6MV X-ray irradiation, and the curves of apoptosis were drawn. The changes in the cell cycles 4, 48, 72, and 96 h after 2-Gy 6MV X-ray irradiation were detected using PI staining flow cytometry. With the increase of irradiation dose, the survival fraction of A549 cells after the application of 0.5 Gy irradiation was decreasing continuously. In comparison to the control group, the apoptosis rate of the ICM-received group was increased in a time-dependent pattern, with the highest apoptosis rate observed at 72 h (p A549 cell damage, indicating that 6MV X-ray irradiation can induce bystander effect on A549 cells, which reaches a peak at 72 h. PMID:25686868

  8. Radioprotection and Cell Cycle Arrest of Intestinal Epithelial Cells by Darinaparsin, a Tumor Radiosensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Junqiang; Doi, Hiroshi [Department of Radiation Oncology, School of Medicine, Stanford University, Stanford, California (United States); Saar, Matthias; Santos, Jennifer [Department of Urology, School of Medicine, Stanford University, Stanford, California (United States); Li, Xuejun; Peehl, Donna M. [Department of Radiation Oncology, School of Medicine, Stanford University, Stanford, California (United States); Knox, Susan J., E-mail: sknox@stanford.edu [Department of Radiation Oncology, School of Medicine, Stanford University, Stanford, California (United States)

    2013-12-01

    Purpose: It was recently reported that the organic arsenic compound darinaparsin (DPS) is a cytotoxin and radiosensitizer of tumor cells in vitro and in subcutaneous xenograft tumors. Surprisingly, it was also found that DPS protects normal intestinal crypt epithelial cells (CECs) from clonogenic death after ionizing radiation (IR). Here we tested the DPS radiosensitizing effect in a clinically relevant model of prostate cancer and explored the radioprotective effect and mechanism of DPS on CECs. Methods and Materials: The radiation modification effect of DPS was tested in a mouse model of orthotopic xenograft prostate cancer and of IR-induced acute gastrointestinal syndrome. The effect of DPS on CEC DNA damage and DNA damage responses was determined by immunohistochemistry. Results: In the mouse model of IR-induced gastrointestinal syndrome, DPS treatment before IR accelerated recovery from body weight loss and increased animal survival. DPS decreased post-IR DNA damage and cell death, suggesting that the radioprotective effect was mediated by enhanced DNA damage repair. Shortly after DPS injection, significant cell cycle arrest was observed in CECs at both G1/S and G2/M checkpoints, which was accompanied by the activation of cell cycle inhibitors p21 and growth arrest and DNA-damage-inducible protein 45 alpha (GADD45A). Further investigation revealed that DPS activated ataxia telangiectasia mutated (ATM), an important inducer of DNA damage repair and cell cycle arrest. Conclusions: DPS selectively radioprotected normal intestinal CECs and sensitized prostate cancer cells in a clinically relevant model. This effect may be, at least in part, mediated by DNA damage response activation and has the potential to significantly increase the therapeutic index of radiation therapy.

  9. Radioprotection and Cell Cycle Arrest of Intestinal Epithelial Cells by Darinaparsin, a Tumor Radiosensitizer

    International Nuclear Information System (INIS)

    Purpose: It was recently reported that the organic arsenic compound darinaparsin (DPS) is a cytotoxin and radiosensitizer of tumor cells in vitro and in subcutaneous xenograft tumors. Surprisingly, it was also found that DPS protects normal intestinal crypt epithelial cells (CECs) from clonogenic death after ionizing radiation (IR). Here we tested the DPS radiosensitizing effect in a clinically relevant model of prostate cancer and explored the radioprotective effect and mechanism of DPS on CECs. Methods and Materials: The radiation modification effect of DPS was tested in a mouse model of orthotopic xenograft prostate cancer and of IR-induced acute gastrointestinal syndrome. The effect of DPS on CEC DNA damage and DNA damage responses was determined by immunohistochemistry. Results: In the mouse model of IR-induced gastrointestinal syndrome, DPS treatment before IR accelerated recovery from body weight loss and increased animal survival. DPS decreased post-IR DNA damage and cell death, suggesting that the radioprotective effect was mediated by enhanced DNA damage repair. Shortly after DPS injection, significant cell cycle arrest was observed in CECs at both G1/S and G2/M checkpoints, which was accompanied by the activation of cell cycle inhibitors p21 and growth arrest and DNA-damage-inducible protein 45 alpha (GADD45A). Further investigation revealed that DPS activated ataxia telangiectasia mutated (ATM), an important inducer of DNA damage repair and cell cycle arrest. Conclusions: DPS selectively radioprotected normal intestinal CECs and sensitized prostate cancer cells in a clinically relevant model. This effect may be, at least in part, mediated by DNA damage response activation and has the potential to significantly increase the therapeutic index of radiation therapy

  10. Disrupted Endothelial Cell Layer and Exposed Extracellular Matrix Proteins Promote Capture of Late Outgrowth Endothelial Progenitor Cells.

    Science.gov (United States)

    Zhao, Jing; Mitrofan, Claudia-Gabriela; Appleby, Sarah L; Morrell, Nicholas W; Lever, Andrew M L

    2016-01-01

    Late outgrowth endothelial progenitor cells (LO-EPC) possess a high proliferative potential, differentiate into vascular endothelial cells (EC), and form networks, suggesting they play a role in vascular repair. However, due to their scarcity in the circulation there is a requirement for ex vivo expansion before they could provide a practical cell therapy and it is currently unclear if they would home and engraft to an injury site. Using an in vitro flow system we studied LO-EPC under simulated injury conditions including EC activation, ischaemia, disrupted EC integrity, and exposed basement membrane. Perfused LO-EPC adhered to discontinuous EC paracellularly at junctional regions between adjacent cells under shear stress 0.7 dyn/cm(2). The interaction was not adhesion molecule-dependent and not enhanced by EC activation. LO-EPC expressed high levels of the VE-Cadherin which may explain these findings. Ischaemia reperfusion injury decreased the interaction with LO-EPC due to cell retraction. LO-EPC interacted with exposed extracellular matrix (ECM) proteins, fibronectin and vitronectin. The interaction was mediated by integrins α5β3, αvβ1, and αvβ3. This study has demonstrated that an injured local environment presents sufficient adhesive signals to capture flow perfused LO-EPC in vitro and that LO-EPC have properties consistent with their potential role in vascular repair. PMID:27413378

  11. Microarray analysis of gene expression in peripheral blood mononuclear cells from dioxin-exposed human subjects

    International Nuclear Information System (INIS)

    Tetrachlorodibenzo-p-dioxin (TCDD) is classified as a human carcinogen and exerts toxic effects on the skin (chloracne). Effects on reproductive, immunological, and endocrine systems have also been observed in animal models. TCDD acts through the aryl hydrocarbon receptor (AhR) pathway influencing largely unknown gene networks. An industrial accident in Seveso, Italy in 1976 exposed thousands of people to substantial quantities of TCDD. Twenty years after the exposure, this study examines global gene expression in the mononuclear cells of 26 Seveso female never smokers, with similar age, alcohol consumption, use of medications, and background plasma levels of 22 dioxin congeners unrelated to the Seveso accident. Plasma dioxin levels were still elevated in the exposed subjects. We performed analyses in two different comparison groups. The first included high-exposed study subjects compared with individuals with background TCDD levels (average plasma levels 99.4 and 6.7 ppt, respectively); the second compared subjects who developed chloracne after the accident, and those who did not develop this disease. Overall, we observed a modest alteration of gene expression based on dioxin levels or on chloracne status. In the comparison between high levels and background levels of TCDD, four histone genes were up-regulated and modified expression of HIST1H3H was confirmed by real-time PCR. In the comparison between chloracne case-control subjects, five hemoglobin genes were up-regulated. Pathway analysis revealed two major networks for each comparison, involving cell proliferation, apoptosis, immunological and hematological disease, and other pathways. Further examination of the role of these genes in dioxin induced-toxicity is warranted

  12. Piperine causes G1 phase cell cycle arrest and apoptosis in melanoma cells through checkpoint kinase-1 activation.

    Directory of Open Access Journals (Sweden)

    Neel M Fofaria

    Full Text Available In this study, we determined the cytotoxic effects of piperine, a major constituent of black and long pepper in melanoma cells. Piperine treatment inhibited the growth of SK MEL 28 and B16 F0 cells in a dose and time-dependent manner. The growth inhibitory effects of piperine were mediated by cell cycle arrest of both the cell lines in G1 phase. The G1 arrest by piperine correlated with the down-regulation of cyclin D1 and induction of p21. Furthermore, this growth arrest by piperine treatment was associated with DNA damage as indicated by phosphorylation of H2AX at Ser139, activation of ataxia telangiectasia and rad3-related protein (ATR and checkpoint kinase 1 (Chk1. Pretreatment with AZD 7762, a Chk1 inhibitor not only abrogated the activation of Chk1 but also piperine mediated G1 arrest. Similarly, transfection of cells with Chk1 siRNA completely protected the cells from G1 arrest induced by piperine. Piperine treatment caused down-regulation of E2F1 and phosphorylation of retinoblastoma protein (Rb. Apoptosis induced by piperine was associated with down-regulation of XIAP, Bid (full length and cleavage of Caspase-3 and PARP. Furthermore, our results showed that piperine treatment generated ROS in melanoma cells. Blocking ROS by tiron protected the cells from piperine mediated cell cycle arrest and apoptosis. These results suggest that piperine mediated ROS played a critical role in inducing DNA damage and activation of Chk1 leading to G1 cell cycle arrest and apoptosis.

  13. Single strand DNA breaks in rat brain cells exposed to microwave radiation

    Energy Technology Data Exchange (ETDEWEB)

    Paulraj, R. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067 (India); Behari, J. [School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067 (India)]. E-mail: jbehari@hotmail.com

    2006-04-11

    This investigation concerns with the effect of low intensity microwave (2.45 and 16.5 GHz, SAR 1.0 and 2.01 W/kg, respectively) radiation on developing rat brain. Wistar rats (35 days old, male, six rats in each group) were selected for this study. These animals were exposed for 35 days at the above mentioned frequencies separately in two different exposure systems. After the exposure period, the rats were sacrificed and the whole brain tissue was dissected and used for study of single strand DNA breaks by micro gel electrophoresis (comet assay). Single strand DNA breaks were measured as tail length of comet. Fifty cells from each slide and two slides per animal were observed. One-way ANOVA method was adopted for statistical analysis. This study shows that the chronic exposure to these radiations cause statistically significant (p < 0.001) increase in DNA single strand breaks in brain cells of rat.

  14. DNA damage induction in human cells exposed to vanadium oxides in vitro.

    Science.gov (United States)

    Rodríguez-Mercado, Juan J; Mateos-Nava, Rodrigo A; Altamirano-Lozano, Mario A

    2011-12-01

    Vanadium and vanadium salts cause genotoxicity and elicit variable biological effects depending on several factors. In the present study, we analyzed and compared the DNA damage and repair processes induced by vanadium in three oxidation states. We used human blood leukocytes in vitro and in a single cell gel electrophoresis assay at two pH values. We observed that vanadium(III) trioxide and vanadium(V) pentoxide produced DNA single-strand breaks at all of the concentrations (1, 2, 4, or 8 μg/ml) and treatment times (2, 4, or 6 h) tested. Vanadium(IV) tetraoxide treatment significantly increased DNA damage at all concentrations for 4 or 6 h of treatment but not for 2 h of treatment. The DNA repair kinetics indicated that most of the cells exposed to vanadium III and V for 4 h recovered within the repair incubation time of 90 min; however, those exposed to vanadium(IV) repaired their DNA within 120 min. The data at pH 9 indicated that vanadium(IV) tetraoxide induced DNA double-strand breaks. Our results show that the genotoxic effect of vanadium can be produced by any of its three oxidation states. However, vanadium(IV) induces double-strand breaks, and it is known that these lesions are linked with forming structural chromosomal aberrations. PMID:21803147

  15. Cell size dynamics and viability of cells exposed to hypotonic treatment and electroporation for electrofusion optimization:

    OpenAIRE

    Hudej, Rosana; Kandušer, Maša; Miklavčič, Damijan; Trontelj, Katja; Ušaj, Marko

    2009-01-01

    Background. Various electrofusion parameters have to be adjusted to obtain theoptimal electrofusion efficiency. Based on published data, good electrofusion conditions can be achieved with the hypotonic treatment. However, the duration of the hypotonic treatment before electroporation and buffer hypoosmolarity have to be adjusted in order to cause cell swelling, to avoid regulatory volume decrease and to preserve cell viability. The aims of our study were to determine cell size dynamics and vi...

  16. Cell size dynamics and viability of cells exposed to hypotonic treatment and electroporation for electrofusion optimization

    OpenAIRE

    Trontelj, Katja; Kandušer, Maša; Miklavčič, Damijan; Hudej, Rosana; Ušaj, Marko

    2015-01-01

    Background. Various electrofusion parameters have to be adjusted to obtain theoptimal electrofusion efficiency. Based on published data, good electrofusion conditions can be achieved with the hypotonic treatment. However, the duration of the hypotonic treatment before electroporation and buffer hypoosmolarity have to be adjusted in order to cause cell swelling, to avoid regulatory volume decrease and to preserve cell viability. The aims of our study were to determine cell size dynamics and vi...

  17. Genotoxic Changes to Rodent Cells Exposed in Vitro to Tungsten, Nickel, Cobalt and Iron

    Directory of Open Access Journals (Sweden)

    Stephanie Bardack

    2014-03-01

    Full Text Available Tungsten-based materials have been proposed as replacements for depleted uranium in armor-penetrating munitions and for lead in small-arms ammunition. A recent report demonstrated that a military-grade composition of tungsten, nickel, and cobalt induced a highly-aggressive, metastatic rhabdomyosarcoma when implanted into the leg muscle of laboratory rats to simulate a shrapnel wound. The early genetic changes occurring in response to embedded metal fragments are not known. In this study, we utilized two cultured rodent myoblast cell lines, exposed to soluble tungsten alloys and the individual metals comprising the alloys, to study the genotoxic effects. By profiling cell transcriptomes using microarray, we found slight, yet distinct and unique, gene expression changes in rat myoblast cells after 24 h metal exposure, and several genes were identified that correlate with impending adverse consequences of ongoing exposure to weapons-grade tungsten alloy. These changes were not as apparent in the mouse myoblast cell line. This indicates a potential species difference in the cellular response to tungsten alloy, a hypothesis supported by current findings with in vivo model systems. Studies examining genotoxic-associated gene expression changes in cells from longer exposure times are warranted.

  18. Protective effect of deoxynucleotide triphosphates on DNA damage in different mammalian cells exposed to -radiation

    Directory of Open Access Journals (Sweden)

    Elmaghraby, T

    2002-09-01

    Full Text Available DNA is generally considered to be the most critical cellular target when considering the lethal, carcinogenic and mutagenic effects of drugs, radiation and environmental chemicals. So the study aim to the determination the damaging effect of -radiation on DNA and the protective effect of deoxynucleotide triphosphates (dNTPs. The study includes three cell types, lymphocytes, kidney cells of African gree monkey (Vero and hepatocellular carcinoma of human (HePG2 exposed to 1-5 Gy of -radiation and by using fluorometric analysis of DNA unwinding (FADU method, DNA damage was measured after radiation. The cells were divided into two groups: The first received 5x10-5 dNTPs from 0-30 minutes after radiation, while the second group was not supplemented with deoxynucleotides. Clonogenic survival for vero and HePG2 cell lines was measured. The results revealed that the increase of irradiation dose precipitates an increase of DNA strand breaks. The slope curve of initial DNA damage and mean inactivation dose (D differ between vero and HepG2 cell line by a factor of up 3.5 and 2, respectively. dNTPs have clear ameliorating effect on DNA damage. FADU method can play an important role in the choice of a suitable treatment (radiation or drugs and its dosage according to measurement of DNA damages in selective malignant tissues. Moreover, using dNTPs mixture can reduce the side effect of these treatment especially after experimentally on live mammals (mice .

  19. [An immunocytochemical study of the C-cell function of the thyroid in rats exposed on the Kosmos-2044 biosatellite].

    Science.gov (United States)

    Loginov, V I

    1993-01-01

    Immunocytochemical analysis of thyroid gland C-cells of the rats exposed to a 14-day space flight revealed a decrease in the number of C-cells, volume of their nuclei and a declined percentage of active secretory C-cells, which point to a decline of calcitonin proactive and calcitonin secretory hypofunction of the thyroid C-cells system in flown rats. Tail suspension as a microgravity model caused similar changes in C-cells. PMID:8012307

  20. Radiosensitizing Effect of TRPV1 Channel Inhibitors in Cancer Cells.

    Science.gov (United States)

    Nishino, Keisuke; Tanamachi, Keisuke; Nakanishi, Yuto; Ide, Shunta; Kojima, Shuji; Tanuma, Sei-Ichi; Tsukimoto, Mitsutoshi

    2016-07-01

    Radiosensitizers are used in cancer therapy to increase the γ-irradiation susceptibility of cancer cells, including radioresistant hypoxic cancer cells within solid tumors, so that radiotherapy can be applied at doses sufficiently low to minimize damage to adjacent normal tissues. Radiation-induced DNA damage is repaired by multiple repair systems, and therefore these systems are potential targets for radiosensitizers. We recently reported that the transient receptor potential vanilloid type 1 (TRPV1) channel is involved in early responses to DNA damage after γ-irradiation of human lung adenocarcinoma A549 cells. Therefore, we hypothesized that TRPV1 channel inhibitors would have a radiosensitizing effect by blocking repair of radiation-induced cell damage. Here, we show that pretreatment of A549 cells with the TRPV1 channel inhibitors capsazepine, AMG9810, SB366791 and BCTC suppressed the γ-ray-induced activation of early DNA damage responses, i.e., activation of the protein kinase ataxia-telangiectasia mutated (ATM) and accumulation of p53-binding protein 1 (53BP1). Further, the decrease of survival fraction at one week after γ-irradiation (2.0 Gy) was enhanced by pretreatment of cells with these inhibitors. On the other hand, inhibitor pretreatment did not affect cell viability, the number of apoptotic or necrotic cells, or DNA synthesis at 24 h after irradiation. These results suggest that inhibition of DNA repair by TRPV1 channel inhibitors in irradiated A549 cells caused gradual loss of proliferative ability, rather than acute facilitation of apoptosis or necrosis. TRPV1 channel inhibitors could be novel candidates for radiosensitizers to improve the efficacy of radiation therapy, either alone or in combination with other types of radiosensitizers. PMID:27150432

  1. p53 modulates the AMPK inhibitor compound C induced apoptosis in human skin cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Shi-Wei [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Wu, Chun-Ying [Division of Gastroenterology and Hepatology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Wang, Yen-Ting [Department of Medical Research and Education, Cheng Hsin General Hospital, Taipei, Taiwan (China); Kao, Jun-Kai [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Department of Pediatrics, Children' s Hospital, Changhua Christian Hospital, Changhua, Taiwan (China); Lin, Chi-Chen; Chang, Chia-Che; Mu, Szu-Wei; Chen, Yu-Yu [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chiu, Husan-Wen [Institute of Biotechnology, National Cheng-Kung University, Tainan, Taiwan (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan (China); Chang, Chuan-Hsun [Department of Surgical Oncology, Cheng Hsin General Hospital, Taipei, Taiwan (China); Department of Nutrition Therapy, Cheng Hsin General Hospital, Taipei, Taiwan (China); School of Nutrition and Health Sciences, Taipei Medical University, Taipei, Taiwan (China); Liang, Shu-Mei [Institute of Biotechnology, National Cheng-Kung University, Tainan, Taiwan (China); Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan (China); Chen, Yi-Ju [Department of Dermatology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Huang, Jau-Ling [Department of Bioscience Technology, Chang Jung Christian University, Tainan, Taiwan (China); Shieh, Jeng-Jer, E-mail: shiehjj@vghtc.gov.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Department of Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan (China)

    2013-02-15

    Compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), has been reported to cause apoptotic cell death in myeloma, breast cancer cells and glioma cells. In this study, we have demonstrated that compound C not only induced autophagy in all tested skin cancer cell lines but also caused more apoptosis in p53 wildtype skin cancer cells than in p53-mutant skin cancer cells. Compound C can induce upregulation, phosphorylation and nuclear translocalization of the p53 protein and upregulate expression of p53 target genes in wildtype p53-expressing skin basal cell carcinoma (BCC) cells. The changes of p53 status were dependent on DNA damage which was caused by compound C induced reactive oxygen species (ROS) generation and associated with activated ataxia-telangiectasia mutated (ATM) protein. Using the wildtype p53-expressing BCC cells versus stable p53-knockdown BCC sublines, we present evidence that p53-knockdown cancer cells were much less sensitive to compound C treatment with significant G2/M cell cycle arrest and attenuated the compound C-induced apoptosis but not autophagy. The compound C induced G2/M arrest in p53-knockdown BCC cells was associated with the sustained inactive Tyr15 phosphor-Cdc2 expression. Overall, our results established that compound C-induced apoptosis in skin cancer cells was dependent on the cell's p53 status. - Highlights: ► Compound C caused more apoptosis in p53 wildtype than p53-mutant skin cancer cells. ► Compound C can upregulate p53 expression and induce p53 activation. ► Compound C induced p53 effects were dependent on ROS induced DNA damage pathway. ► p53-knockdown attenuated compound C-induced apoptosis but not autophagy. ► Compound C-induced apoptosis in skin cancer cells was dependent on p53 status.

  2. p53 modulates the AMPK inhibitor compound C induced apoptosis in human skin cancer cells

    International Nuclear Information System (INIS)

    Compound C, a well-known inhibitor of the intracellular energy sensor AMP-activated protein kinase (AMPK), has been reported to cause apoptotic cell death in myeloma, breast cancer cells and glioma cells. In this study, we have demonstrated that compound C not only induced autophagy in all tested skin cancer cell lines but also caused more apoptosis in p53 wildtype skin cancer cells than in p53-mutant skin cancer cells. Compound C can induce upregulation, phosphorylation and nuclear translocalization of the p53 protein and upregulate expression of p53 target genes in wildtype p53-expressing skin basal cell carcinoma (BCC) cells. The changes of p53 status were dependent on DNA damage which was caused by compound C induced reactive oxygen species (ROS) generation and associated with activated ataxia-telangiectasia mutated (ATM) protein. Using the wildtype p53-expressing BCC cells versus stable p53-knockdown BCC sublines, we present evidence that p53-knockdown cancer cells were much less sensitive to compound C treatment with significant G2/M cell cycle arrest and attenuated the compound C-induced apoptosis but not autophagy. The compound C induced G2/M arrest in p53-knockdown BCC cells was associated with the sustained inactive Tyr15 phosphor-Cdc2 expression. Overall, our results established that compound C-induced apoptosis in skin cancer cells was dependent on the cell's p53 status. - Highlights: ► Compound C caused more apoptosis in p53 wildtype than p53-mutant skin cancer cells. ► Compound C can upregulate p53 expression and induce p53 activation. ► Compound C induced p53 effects were dependent on ROS induced DNA damage pathway. ► p53-knockdown attenuated compound C-induced apoptosis but not autophagy. ► Compound C-induced apoptosis in skin cancer cells was dependent on p53 status

  3. Comet-FISH with strand-specific probes reveals transcription-coupled repair of 8-oxoGuanine in human cells

    Science.gov (United States)

    Guo, Jia; Hanawalt, Philip C.; Spivak, Graciela

    2013-01-01

    Oxidized bases in DNA have been implicated in cancer, aging and neurodegenerative disease. We have developed an approach combining single-cell gel electrophoresis (comet) with fluorescence in situ hybridization (FISH) that enables the comparative quantification of low, physiologically relevant levels of DNA lesions in the respective strands of defined nucleotide sequences and in the genome overall. We have synthesized single-stranded probes targeting the termini of DNA segments of interest using a polymerase chain reaction-based method. These probes facilitate detection of damage at the single-molecule level, as the lesions are converted to DNA strand breaks by lesion-specific endonucleases or glycosylases. To validate our method, we have documented transcription-coupled repair of cyclobutane pyrimidine dimers in the ataxia telangiectasia-mutated (ATM) gene in human fibroblasts irradiated with 254 nm ultraviolet at 0.1 J/m2, a dose ∼100-fold lower than those typically used. The high specificity and sensitivity of our approach revealed that 7,8-dihydro-8-oxoguanine (8-oxoG) at an incidence of approximately three lesions per megabase is preferentially repaired in the transcribed strand of the ATM gene. We have also demonstrated that the hOGG1, XPA, CSB and UVSSA proteins, as well as actively elongating RNA polymerase II, are required for this process, suggesting cross-talk between DNA repair pathways. PMID:23775797

  4. Functional switching of ATM: sensor of DNA damage in proliferating cells and mediator of Akt survival signal in post-mitotic human neuron-like cells

    Institute of Scientific and Technical Information of China (English)

    Yan Li; Hua Xiong; Da-Qing Yang

    2012-01-01

    Ataxia-telangiectasia (A-T) is an autosomal recessive disorder characterized by cerebellar ataxia and oculocutaneous telangiectasias.The gene mutated in this disease,ATM (A-T,mutated),encodes a 370-kDa Ser/Thr protein kinase.ATM not only mediates cellular response to DNA damage but also acts as an activator of Akt in response to insulin.However,despite intensive studies,the mechanism underlying the neuronal degeneration symptoms of human A-T is still poorly understood.We found that the topoisomerase inhibitors etoposide and camptothecin readily induced apoptosis in undifferentiated proliferating SH-SY5Y cells but could not induce apoptosis in neuronally differentiated SH-SY5Y cells.In addition,etoposide induced p53 phosphorylation and H2AX foci formation in proliferating SH-SY5Y cells but failed to do so in differentiated SH-SY5Y cells.Moreover,while inhibition of ATM in undifferentiated SH-SY5Y cells partially protected them from etoposide-induced apoptosis,the same treatment had no effect on cell viability in differentiated SH-SY5Y cells.These results suggest that DNA damage or defective response to DNA damage is not the cause of neuronal cell death in human A-T.In contrast,we discovered that Akt phosphorylation was inhibited when ATM activity was suppressed in differentiated SH-SY5Y cells.Furthermore,inhibition of ATM induced apoptosis following serum starvation in neuronally differentiated SH-SY5Y cells but could not trigger apoptosis under the same conditions in undifferentiated proliferating SH-SY5Y cells.These results demonstrate that ATM mediates the Akt signaling and promotes cell survival in neuron-like human SH-SY5Y cells,suggesting that impaired activation of Akt is the reason for neuronal degeneration in human A-T.

  5. Dose and temporal effects on gene expression profiles of urothelial cells from rats exposed to diuron

    International Nuclear Information System (INIS)

    Diuron (3-(3,4-dichlorophenyl)-1,1-dimethylurea) is a substituted urea herbicide that at high dietary levels (2500 ppm) induces rat urinary bladder hyperplasia after 20 weeks of exposure and neoplasia after 2 years. The effects on the urothelium after short-term exposure have not been described. The present 7-day study evaluated the dose-dependency of urothelial alterations in the urinary bladder using light microscopy, scanning electron microscopy, and genome-wide transcriptional profiling. Male Wistar rats were fed 0, 125, 500, 2500 ppm diuron for 7 days. The urinary bladder and isolated urothelial cells of these animals were processed for microscopic examination and gene expression profiling, respectively. No significant treatment-related morphologic effects were observed. The number of differentially expressed genes (DEGs) in the exposed groups increased with diuron levels. Diuron-altered genes involved in cell-to-cell interactions and tissue organization were identified in all treatment groups. After 7 days of diuron exposure, transcriptional responses were observed in the urothelium in the absence of clear morphologic changes. These morphological findings are different from those observed in a previous study in which 20 weeks of diuron exposure was associated with simple hyperplasia secondary to the persistent cytotoxicity and necrosis associated with continuous cellular regeneration. Comparison of the gene expression profiles of rats exposed to the 2500 ppm carcinogenic diuron dose for 7 days versus 20 weeks revealed few similarities between these two time points at the gene or pathway level. Taken together, these data provide insight into the dose- and temporal-dependent morphological and transcriptional changes associated with diuron exposure that may lead to the development of tumors in the rat urinary bladder

  6. Global gene expression profiling in human lung cells exposed to cobalt

    Directory of Open Access Journals (Sweden)

    Steinmetz Gerard

    2007-06-01

    Full Text Available Abstract Background It has been estimated that more than 1 million workers in the United States are exposed to cobalt. Occupational exposure to 59 Co occurs mainly via inhalation and leads to various lung diseases. Cobalt is classified by the IARC as a possible human carcinogen (group 2B. Although there is evidence for in vivo and in vitro toxicity, the mechanisms of cobalt-induced lung toxicity are not fully known. The purpose of this work was to identify potential signatures of acute cobalt exposure using a toxicogenomic approach. Data analysis focused on some cellular processes and protein targets that are thought to be relevant for carcinogenesis, transport and biomarker research. Results A time course transcriptome analysis was performed on A549 human pulmonary cells, leading to the identification of 85 genes which are repressed or induced in response to soluble 59 Co. A group of 29 of these genes, representing the main biological functions, was assessed by quantitative RT-PCR. The expression profiles of six of them were then tested by quantitative RT-PCR in a time-dependent manner and three modulations were confirmed by Western blotting. The 85 modulated genes include potential cobalt carriers (FBXL2, ZNT1, SLC12A5, tumor suppressors or transcription factors (MAZ, DLG1, MYC, AXL and genes linked to the stress response (UBC, HSPCB, BNIP3L. We also identified nine genes coding for secreted proteins as candidates for biomarker research. Of those, TIMP2 was found to be down-regulated and this modulation was confirmed, in a dose-dependent manner, at protein level in the supernatant of exposed cells. Conclusion Most of these genes have never been described as related to cobalt stress and provide original hypotheses for further study of the effects of this metal ion on human lung epithelial cells. A putative biomarker of cobalt toxicity was identified.

  7. Normal human monocytes exposed to glioma cells acquire myeloid-derived suppressor cell-like properties

    OpenAIRE

    Rodrigues, Jennifer C.; Gonzalez, Guido C.; Zhang, Lei; Ibrahim, George; Kelly, John J.; Gustafson, Michael P.; Yi LIN; Dietz, Allan B.; Forsyth, Peter A; Yong, V. Wee; Parney, Ian F.

    2009-01-01

    Glioblastoma patients are immunosuppressed, yet glioblastomas are highly infiltrated by monocytes/macrophages. Myeloid-derived suppressor cells (MDSC; immunosuppressive myeloid cells including monocytes) have been identified in other cancers and correlate with tumor burden. We hypothesized that glioblastoma exposure causes normal monocytes to assume an MDSC-like phenotype and that MDSC are increased in glioblastoma patients. Healthy donor human CD14+ monocytes were cultured with human gliobla...

  8. Human epithelial cells exposed to functionalized multiwalled carbon nanotubes: interactions and cell surface modifications.

    Science.gov (United States)

    Fanizza, C; Casciardi, S; Incoronato, F; Cavallo, D; Ursini, C L; Ciervo, A; Maiello, R; Fresegna, A M; Marcelloni, A M; Lega, D; Alvino, A; Baiguera, S

    2015-09-01

    With the expansion of the production and applications of multiwalled carbon nanotubes (MWCNTs) in several industrial and science branches, the potential adverse effects on human health have attracted attention. Numerous studies have been conducted to evaluate how chemical functionalization may affect MWCNT effects; however, controversial data have been reported, showing either increased or reduced toxicity. In particular, the impact of carboxylation on MWCNT cytotoxicity is far from being completely understood. The aim of this work was the evaluation of the modifications induced by carboxylated-MWCNTs (MWCNTs-COOH) on cell surface and the study of cell-MWCNT-COOH interactions by means of field emission scanning electron microscope (FESEM). Human pulmonary epithelial cells (A549) were incubated with MWCNTs-COOH for different exposure times and concentrations (10 μg/mL for 1, 2, 4 h; 5, 10, 20 μg/mL for 24 h). At short incubation time, MWCNTs-COOH were easily observed associated with plasma membrane and in contact with microvilli. After 24 h exposure, FESEM analysis revealed that MWCNTs-COOH induced evident changes in the cellular surface in comparison to control cells: treated cells showed blebs, holes and a depletion of the microvilli density in association with structure modifications, such as widening and/or lengthening. In particular, an increase of cells showing holes and microvilli structure alterations was observed at 20 μg/mL concentration. FESEM analysis showed nanotube agglomerates, of different sizes, entering into the cell with two different mechanisms: inward bending of the membrane followed by nanotube sinking, and nanotube internalization directly through holes. The observed morphological microvilli modifications, induced by MWCNTs-COOH, could affect epithelial functions, such as the control of surfactant production and secretion, leading to pathological conditions, such as alveolar proteinosis. More detailed studies will be, however, necessary to

  9. EVALUATION OF CELL CYCLE OF Aspergillus nidulans EXPOSED TO THE EXTRACT OF Copaifera officinalis L PLANT

    Directory of Open Access Journals (Sweden)

    Simone Jurema Ruggeri Chiuchetta, Uériton Dias de Oliveira e Josy Fraccaro de Marins

    2006-12-01

    Full Text Available The oil extracted from the Copaifera officinalis L plant has been used in popular medicine to the treatment of several diseases, like cancer. In eukaryotic cells, the process of cellular proliferation follows a standard cycle, named cellular cycle. The transformation of a normal cell in a malignant one requires several steps, in which genes that control normal cellular division or cellular death are modified. Aspergillus nidulans fungus is an excellent system for the study of the cellular differentiation. Its asexual cycle results in the formation of conidia, which are disposed like chains, constituting a structure named conidiophore. This structure consists in an aerial hifae, multinucleate vesicle and uninucleate cells. Current research evaluated the capacity of the C. officinalis L plant extract in promoting alterations in the cellular cycle of A. nidulans diploid strains, by observing macroscopic and microscopic alterations in cellular growth of this fungus. Results shown that no macroscopic alterations were observed in cellular growth of strains exposed to the extract, however, microscopic alterations of conidiophore have been observed in the different extract concentrations analyzed. In this way, the study of the action of C. officinalis L plant extract becomes important considering the fact that this substance is capable to promote alterations in cellular cycle of eukaryotic cells.

  10. Killing effect of Chinese hamster V79 cells exposed to accelerated carbon ions and RBE determination

    Institute of Scientific and Technical Information of China (English)

    LIQiang; ZHOUGuang-Ming; 等

    2002-01-01

    Survival curves of Chinese hamster V79 cells exposed to accelerated carbon ions with linear energy transfers of 125.5,200 and 700keV/um were measured,respectively,Inactivation cross sections corresponding to the irradiation above were deduced from the V79 cell survival curves.They are 7.86±0.17,10.44±1.11 and 32.32±3.59um2 in turn.With the surviving response of V79 cells to 60Co γ-rays as a reference value,relative biological effectiveness at 10%,20%,50%and 80% survival levels were given for the accelerated carbon ions,The results showed that carbon ions with LET of 125.5keV/um had a higher value of RBE at all the four survival levels than the carbon ions with other LETs.It was prompted that the maximum value of RBE for the V79 cell surviving as the biological endpoint emerged at the LET below 200keV/um for carbon ions.

  11. Killing effect of Chinese hamster V79 cells exposed to accelerated carbon ions and RBE determination

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Survival curves of Chinese hamster V79 cells exposed to accclerated carbon ions with linear energy transfers of 125.5, 200 and 700 keV/μm were measured, respectively. Inactivation cross sections corresponding to the irradiation above were deduced from the V79 cell survival curves. They are 7.86±0.17, 10.44±1.11 and 32.32±3.58 μm2 in turn. With the surviving response of V79 cells to 60Co γ-rays as a reference value, relative biological effectiveness at 10%, 20%, 50% and 80% survival levels were given for the accelerated carbon ions. The results showed that carbon ions with LET of 125.5 keV/μm had a higher value of RBE at all the four survival levels than the carbon ions with other LETs. It was prompted that the maximum value of RBE for the V79 cell surviving as the biological endpoint emerged at the LET below 200 keV/μm for carbon ions.

  12. Low dose ionizing radiation responses and knockdown of ATM kinase activity in glioma stem cells

    International Nuclear Information System (INIS)

    Genesis of new cells in the mammalian brain has previously been regarded as a negligible event; an assumption that long limited our understanding in the development of neoplasias. The recent discovery of perpetual lineages derived from neural stem cells has resulted in a new approach to studying the cellular behaviour of potential cancer stem cells in the brain. Glioblastoma multiforme (GBM), the most aggressive and lethal brain tumour is derived from a group of cancerous stem cells known as glioma stem cells. GBM cells are impervious to conventional therapies such as surgical resection and ionizing radiation because of their pluripotent and radioresistant properties. Thus in our study, we aim to investigate whether a combination of chemo- and radio- therapies is an effective treatment for glioma stem cells. The study utilizes a specific kinase inhibitor (ATMi) of the ATM (Ataxia-telangiectasia mutated) protein which is an essential protein in DNA-damage responses. In the presence of both low dose radiation and ATMi, glioma stem cells have rapid onset of cell death and reduction in growth. Since DNA damage can be inherited through cell division, accumulated DNA breaks in later generations may also lead to cell death. The limitation of conventional radiation therapy is that administration of fractionated (low) doses to reduce any potential harm to the surrounding healthy cells in the brain outweighs the benefits of high radiation doses to induce actual arrest in the propagation of malignant cells. Our study demonstrates a benefit in using low dose radiation combined with chemotherapy resulting in a reduction in malignancy of glioma stem cells. (author)

  13. Capacity of ultraviolet-induced DNA repair in human glioma cells

    International Nuclear Information System (INIS)

    A DNA repair abnormality is likely related to an increased incidence of neoplasms in several autosomal recessive diseases such as xeroderma pigmentosum, Fanconi's anemia, Bloom's syndrome and ataxia telangiectasia. In human glioma cells, however, there are only a few reports on DNA repair. In this study, an ultraviolet (UV)-induced DNA repair was examined systematically in many human glioma cells. Two human malignant glioma cell lines (MMG-851, U-251-MG) and 7 human glioma cell strains (4, benign; 3, malignant) of short term culture, in which glial fibrillary acidic protein (GFAP) staining were positive, were used. To investigate the capacity of DNA repair, UV sensitivity was determined by colony formation; excision repair by autoradiography and Cytosine Arabinoside (Ara-C) assay; and post-replication repair by the joining rate of newly synthesized DNA. As a result, the colony-forming abilities of malignant glioma cell lines were lower than those of normal human fibroblasts, but no difference was found between two malignant glioma cell lines. The excision repair of the malignant group (2 cell lines and 3 cell strains) was apparently lower than that of the benign group (4 cell strains). In two malignant glioma cell lines, the excision repair of MMG-851 was lower than that of U-251-MG, and the post-replication repair of MMG-851 was higher than that of U-251-MG. These results were considered to correspond well with colony-forming ability. The results indicate that there are some differences in each human malignant glioma cell in its UV-induced DNA repair mechanism, and that the excision repair of the malignant glioma cells is apparently lower than that of the benign glioma cells. These findings may be useful for diagnosis and treatment. (author)

  14. The Bioeffects Resulting from Prokaryotic Cells and Yeast Being Exposed to an 18 GHz Electromagnetic Field

    Science.gov (United States)

    Pham, Vy T. H.; Nguyen, Song Ha; Baulin, Vladimir; Croft, Rodney J.; Phillips, Brian; Crawford, Russell J.

    2016-01-01

    The mechanisms by which various biological effects are triggered by exposure to an electromagnetic field are not fully understood and have been the subject of debate. Here, the effects of exposing typical representatives of the major microbial taxa to an 18 GHz microwave electromagnetic field (EMF)were studied. It appeared that the EMF exposure induced cell permeabilisation in all of the bacteria and yeast studied, while the cells remained viable (94% throughout the exposure), independent of the differences in cell membrane fatty acid and phospholipid composition. The resulting cell permeabilisation was confirmed by detection of the uptake of propidium iodine and 23 nm fluorescent silica nanospheres using transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Upon EMF exposure, the bacterial cell membranes are believed to become permeable through quasi-endocytosis processes. The dosimetry analysis revealed that the EMF threshold level required to induce the uptake of the large (46 nm) nanopsheres was between three and six EMF doses, with a specific absorption rate (SAR) of 3 kW/kg and 5 kW/kg per exposure, respectively, depending on the bacterial taxa being studied. It is suggested that the taxonomic affiliation and lipid composition (e.g. the presence of phosphatidyl-glycerol and/or pentadecanoic fatty acid) may affect the extent of uptake of the large nanospheres (46 nm). Multiple 18 GHz EMF exposures over a one-hour period induced periodic anomalous increases in the cell growth behavior of two Staphylococcus aureus strains, namely ATCC 25923 and CIP 65.8T. PMID:27391488

  15. Increased GADD gene expression in human colon epithelial cells exposed to deoxycholate.

    Science.gov (United States)

    Scott, David W; Mutamba, Sophia; Hopkins, Robin G; Loo, George

    2005-01-01

    The colonic epithelium is often exposed to high concentrations of secondary bile acids, which stresses the epithelial cells, leading potentially to activation of stress-response genes. To examine this possibility in vitro, the purpose of this study was to determine if expression of certain growth arrest and DNA damage-inducible genes (GADD) is upregulated in human colonic epithelial cells exposed to deoxycholate (DOC). DNA macroarray screening of a small cluster of stress/apoptosis-related genes in DOC-treated HCT-116 colonocytes revealed clearly higher expression of only GADD45, which was confirmed by gene-specific relative RT-PCR analysis. Subsequently, it was found that DOC also increased GADD34 mRNA expression. However, mRNA expression of GADD153 was increased most markedly in DOC-treated HCT-116 colonocytes, which express wild-type p53. However, the upregulation of GADD34, GADD45, and GADD153 mRNA expression apparently did not require p53, based on the finding that DOC increased expression of all three GADD genes in HCT-15 colonocytes, which express mutant p53. In further studying GADD153 in particular, the effect of DOC on GADD153 mRNA was prevented by actinomycin-D (Act-D), but not by antioxidants or MAPK inhibitors. DOC also caused GADD153 protein to be expressed in close parallel with increased GADD153 mRNA expression. Induction of GADD153 protein by DOC was prevented by either anisomycin or cycloheximide. These findings suggest that DOC-induced upregulation of GADD153 mRNA expression occurred at the level of transcription without involving reactive oxygen species and MAPK signaling, and that the expression of GADD153 protein was due also to translation of pre-existing, and not just newly synthesized, mRNA. PMID:15316935

  16. Oxidative stress response in neural stem cells exposed to different superparamagnetic iron oxide nanoparticles

    Science.gov (United States)

    Pongrac, Igor M; Pavičić, Ivan; Milić, Mirta; Brkić Ahmed, Lada; Babič, Michal; Horák, Daniel; Vinković Vrček, Ivana; Gajović, Srećko

    2016-01-01

    Biocompatibility, safety, and risk assessments of superparamagnetic iron oxide nanoparticles (SPIONs) are of the highest priority in researching their application in biomedicine. One improvement in the biological properties of SPIONs may be achieved by different functionalization and surface modifications. This study aims to investigate how a different surface functionalization of SPIONs – uncoated, coated with d-mannose, or coated with poly-l-lysine – affects biocompatibility. We sought to investigate murine neural stem cells (NSCs) as important model system for regenerative medicine. To reveal the possible mechanism of toxicity of SPIONs on NSCs, levels of reactive oxygen species, intracellular glutathione, mitochondrial membrane potential, cell-membrane potential, DNA damage, and activities of SOD and GPx were examined. Even in cases where reactive oxygen species levels were significantly lowered in NSCs exposed to SPIONs, we found depleted intracellular glutathione levels, altered activities of SOD and GPx, hyperpolarization of the mitochondrial membrane, dissipated cell-membrane potential, and increased DNA damage, irrespective of the surface coating applied for SPION stabilization. Although surface coating should prevent the toxic effects of SPIONs, our results showed that all of the tested SPION types affected the NSCs similarly, indicating that mitochondrial homeostasis is their major cellular target. Despite the claimed biomedical benefits of SPIONs, the refined determination of their effects on various cellular functions presented in this work highlights the need for further safety evaluations. This investigation helps to fill the knowledge gaps on the criteria that should be considered in evaluating the biocompatibility and safety of novel nanoparticles.

  17. Investigation of micronucleus induction in MTH1 knockdown cells exposed to UVA, UVB or UVC.

    Science.gov (United States)

    Fotouhi, Asal; Cornella, Nicola; Ramezani, Mehrafarin; Wojcik, Andrzej; Haghdoost, Siamak

    2015-11-01

    The longer wave parts of UVR can increase the production of reactive oxygen species (ROS) which can oxidize nucleotides in the DNA or in the nucleotide pool leading to mutations. Oxidized bases in the DNA are repaired mainly by the DNA base excision repair system and incorporation of oxidized nucleotides into newly synthesized DNA can be prevented by the enzyme MTH1. Here we hypothesize that the formation of several oxidized base damages (from pool and DNA) in close proximity, would cause a high number of base excision repair events, leading to DNA double strand breaks (DSB) and therefore giving rise to cytogenetic damage. If this hypothesis is true, cells with low levels of MTH1 will show higher cytogenetic damage after the longer wave parts of UVR. We analyzed micronuclei induction (MN) as an endpoint for cytogenetic damage in the human lymphoblastoid cell line, TK6, with a normal and a reduced level of MTH1 exposed to UVR. The results indicate a higher level of micronuclei at all incubation times after exposure to the longer wave parts of UVR. There is no significant difference between wildtype and MTH1-knockdown TK6 cells, indicating that MTH1 has no protective role in UVR-induced cytogenetic damage. This indicates that DSBs induced by UV arise from damage forms by direct interaction of UV or ROS with the DNA rather than through oxidation of dNTP. PMID:26520386

  18. Oxidative stress response in neural stem cells exposed to different superparamagnetic iron oxide nanoparticles.

    Science.gov (United States)

    Pongrac, Igor M; Pavičić, Ivan; Milić, Mirta; Brkić Ahmed, Lada; Babič, Michal; Horák, Daniel; Vinković Vrček, Ivana; Gajović, Srećko

    2016-01-01

    Biocompatibility, safety, and risk assessments of superparamagnetic iron oxide nanoparticles (SPIONs) are of the highest priority in researching their application in biomedicine. One improvement in the biological properties of SPIONs may be achieved by different functionalization and surface modifications. This study aims to investigate how a different surface functionalization of SPIONs - uncoated, coated with d-mannose, or coated with poly-l-lysine - affects biocompatibility. We sought to investigate murine neural stem cells (NSCs) as important model system for regenerative medicine. To reveal the possible mechanism of toxicity of SPIONs on NSCs, levels of reactive oxygen species, intracellular glutathione, mitochondrial membrane potential, cell-membrane potential, DNA damage, and activities of SOD and GPx were examined. Even in cases where reactive oxygen species levels were significantly lowered in NSCs exposed to SPIONs, we found depleted intracellular glutathione levels, altered activities of SOD and GPx, hyperpolarization of the mitochondrial membrane, dissipated cell-membrane potential, and increased DNA damage, irrespective of the surface coating applied for SPION stabilization. Although surface coating should prevent the toxic effects of SPIONs, our results showed that all of the tested SPION types affected the NSCs similarly, indicating that mitochondrial homeostasis is their major cellular target. Despite the claimed biomedical benefits of SPIONs, the refined determination of their effects on various cellular functions presented in this work highlights the need for further safety evaluations. This investigation helps to fill the knowledge gaps on the criteria that should be considered in evaluating the biocompatibility and safety of novel nanoparticles. PMID:27217748

  19. Immunotropic potency of microwave fields: preliminary studies on immunocompetent cells exposed in vitro

    International Nuclear Information System (INIS)

    Exposure in radiofrequency (RF) and microwave (MW) fields can influence the function of the immune system, but the data available on the immunotropic potency of RF/MW radiation are still full of uncertainties and controversies. In the available literature there exist no reports on complex assessment of function and responsiveness of the immune system. All investigations have been aimed to evaluate selected, fragmentary reaction of the system and/or functional response of immunocompetent cells in RF/MW-exposed subjects. However, at the present state of knowledge it is not possible to conclude about the possible immunotropic potencies of RF/MW radiation. The undisturbed defensive, tolerogenic, and proregenerative activities of the immune system are commonly recognised as one of the most important homeostatic functions of the organism. Thus, basic immunoregulatory activities which can be observed and precisely quantified in microcultures of immune cells separated from the human blood, represent a unique and objective model for the investigation of possible immunotropic effects of electromagnetic fields (EMFs). To determine the potential immunomodulatory influences of EMFs, the immunotropic effects of pulse modulated microwave (1300 MHz) were investigated in the cultures of blood mononuclear cells from sixteen healthy donors

  20. Genome-wide gene expression analysis of mouse embryonic stem cells exposed to p-dichlorobenzene.

    Science.gov (United States)

    Tani, Hidenori; Takeshita, Jun-Ichi; Aoki, Hiroshi; Abe, Ryosuke; Toyoda, Akinobu; Endo, Yasunori; Miyamoto, Sadaaki; Gamo, Masashi; Torimura, Masaki

    2016-09-01

    Because of the limitations of whole animal testing approaches for toxicological assessment, new cell-based assay systems have been widely studied. In this study, we focused on two biological products for toxicological assessment: mouse embryonic stem cells (mESCs) and long noncoding RNAs (lncRNAs). mESCs possess the abilities of self-renewal and differentiation into multiple cell types. LlncRNAs are an important class of pervasive non-protein-coding transcripts involved in the molecular mechanisms associated with responses to chemicals. We exposed mESCs to p-dichlorobenzene (p-DCB) for 1 or 28 days (daily dose), extracted total RNA, and performed deep sequencing analyses. The genome-wide gene expression analysis indicated that mechanisms modulating proteins occurred following acute and chronic exposures, and mechanisms modulating genomic DNA occurred following chronic exposure. Moreover, our results indicate that three novel lncRNAs (Snora41, Gm19947, and Scarna3a) in mESCs respond to p-DCB exposure. We propose that these lncRNAs have the potential to be surrogate indicators of p-DCB responses in mESCs. PMID:26975756

  1. Anti-inflammatory activity of the basolateral fraction of Caco-2 cells exposed to a rosemary supercritical extract

    NARCIS (Netherlands)

    Arranz, E.; Mes, J.J.; Wichers, H.J.; Jaime, L.; Reglero, G.; Santoyo, S.

    2015-01-01

    The anti-inflammatory activity of the basolateral fraction of Caco-2 cells exposed to a rosemary supercritical extract was examined. Uptake of rosemary extract fractions was tested on Caco-2 cell monolayers (2–12 h incubation times) and the quantification of carnosic acid and carnosol was performed

  2. AT cells are not radiosensitive for simple chromosomal exchanges at low dose

    Energy Technology Data Exchange (ETDEWEB)

    Hada, Megumi; Huff, Janice L.; Patel, Zarana S. [USRA Division of Life Sciences, Houston, TX 77058 (United States); Kawata, Tetsuya [Department of Radiology, School of Medicine, Keio University, Tokyo (Japan); Pluth, Janice M. [Lawrence Berkeley National Laboratory, Life Sciences Division, One Cyclotron Road, Building 74, Berkeley, CA 94720 (United States); George, Kerry A. [Wyle, 1290 Hercules Drive, Houston, TX 77058 (United States); Cucinotta, Francis A., E-mail: Francis.A.Cucinotta@nasa.gov [NASA, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, TX 77058 (United States)

    2011-11-01

    Cells deficient in ATM (product of the gene that is mutated in ataxia telangiectasia patients) or NBS (product of the gene mutated in the Nijmegen breakage syndrome) show increased yields of both simple and complex chromosomal aberrations after high doses (>0.5 Gy) of ionizing radiation (X-rays or {gamma}-rays), however less is known on how these cells respond at low dose. Previously we had shown that the increased chromosome aberrations in ATM and NBS defective lines was due to a significantly larger quadratic dose-response term compared to normal fibroblasts for both simple and complex exchanges. The linear dose-response term for simple exchanges was significantly higher in NBS cells compared to wild type cells, but not for AT cells. However, AT cells have a high background level of exchanges compared to wild type or NBS cells that confounds the understanding of low dose responses. To understand the sensitivity differences for high to low doses, chromosomal aberration analysis was first performed at low dose-rates (0.5 Gy/d), and results provided further evidence for the lack of sensitivity for exchanges in AT cells below doses of 1 Gy. Normal lung fibroblast cells treated with KU-55933, a specific ATM kinase inhibitor, showed increased numbers of exchanges at a dose of 1 Gy and higher, but were similar to wild type cells at 0.5 Gy or below. These results were confirmed using siRNA knockdown of ATM. The present study provides evidence that the increased radiation sensitivity of AT cells for chromosomal exchanges found at high dose does not occur at low dose.

  3. Cytogenomics of hexavalent chromium (Cr6+ exposed cells: A comprehensive review

    Directory of Open Access Journals (Sweden)

    Akanksha Nigam

    2014-01-01

    Full Text Available The altered cellular gene expression profile is being hypothesized as the possible molecular basis navigating the onset or progress of various morbidities. This hypothesis has been evaluated here in respect of Cr 6+ induced toxicity. Several studies using gene microarray show selective and strategic dysregulations of cellular genes and pathways induced by Cr 6+ . Relevant literature has been reviewed to unravel these changes in different test systems after exposure to Cr 6+ and also to elucidate association if any, of the altered cytogenomics with Cr 6+ induced toxicity or carcinogenicity. The aim was to verify the hypothesis for critical role of altered cytogenomics in onset of Cr 6+ induced biological / clinical effects by identifying genes modulated commonly by the toxicant irrespective of test system or test concentrations / doses, and by scrutinizing their importance in regulation of the flow of mechanistically linked events crucial for resultant morbidities. Their probability as biomarkers to monitor the toxicant induced biological changes is speculative. The modulated genes have been found to cluster under the pathways that manage onset of oxidative stress, DNA damage, apoptosis, cell-cycle regulation, cytoskeleton, morphological changes, energy metabolism, biosynthesis, oncogenes, bioenergetics, and immune system critical for toxicity. In these studies, the identity of genes has been found to differ remarkably; albeit the trend of pathways′ dysregulation has been found to remain similar. We conclude that the intensity of dysregulation of genes or pathways involved in mechanistic events forms a sub-threshold or threshold level depending upon the dose and type (including speciation of the toxicant, duration of exposure, type of target cells, and niche microenvironment of cells, and the intensity of sub-threshold or threshold level of the altered cytogenomics paves way in toxicant exposed cells eventually either to opt for reversal to

  4. Enhanced inhibition of parvovirus B19 replication by cidofovir in extendedly exposed erythroid progenitor cells.

    Science.gov (United States)

    Bonvicini, Francesca; Bua, Gloria; Manaresi, Elisabetta; Gallinella, Giorgio

    2016-07-15

    Human parvovirus B19 (B19V) commonly induces self-limiting infections but can also cause severe clinical manifestations in patients with underlying haematological disorders or with immune system deficits. Currently, therapeutic options for B19V entirely rely on symptomatic and supportive treatments since a specific antiviral therapy is not yet available. Recently a first step in the research for active compounds inhibiting B19V replication has allowed identifying the acyclic nucleoside phosphonate cidofovir (CDV). Herein, the effect of CDV against B19V replication was characterized in human erythroid progenitor cells (EPCs) cultured and infected following different experimental approaches to replicate in vitro the infection of an expanding erythroid cell population in the bone marrow. B19V replication was selectively inhibited both in infected EPCs extendedly exposed to CDV 500μM (viral inhibition 82%) and in serially infected EPCs cultures with passage of the virus progeny, constantly under drug exposure (viral inhibition 99%). In addition, a potent inhibitory effect against B19V (viral inhibition 92%) was assessed in a short-term infection of EPCs treated with CDV 500μM 1day before viral infection. In the evaluated experimental conditions, the enhanced effect of CDV against B19V might be ascribed both to the increased intracellular drug concentration achieved by extended exposure, and to a progressive reduction in efficiency of the replicative process within treated EPCs population. PMID:27071853

  5. Radiosensitization of mammalian cells by misonidazole and oxygen: DNA damage exposed by Micrococcus luteus enzymes

    International Nuclear Information System (INIS)

    When misonidazole is present during irradiation of hypoxic mammalian cells, an enhancement of single-strand breaks (SSB) in DNA is observed. Oxygen also enhances SSB, presumably in a manner similar to that of misonidazole. The dose-modifying factor (DMF) for 15 mM misonidazole was found to be 3.4, compared to an oxygen enhancement ratio (OER) of 3.5. Another class of DNA damage, namely, sites exposed by an extract of Micrococcus luteus, was examined. Radiation-induced M. luteus extract-sensitive sites (MLS) were also found to be enhanced by the presence of misonidazole or molecular oxygen. The DMF for this damage by 15 mM misonidazole was 1.6 while the OER was 2.5. The ratio of MLS to SSB is approximately 1.25 under hypoxia, 0.9 in the presence of oxygen, and 0.6 in the presence of 15 mM misonidazole under hypoxic conditions. Incubation with misonidazole under conditions which are toxic to mammalian cells (370C, hypoxia), and which result in many SSB, produces no detectable lesions sensitive to the M. luteus extract

  6. The Roles of 4β-Hydroxywithanolide E from Physalis peruviana on the Nrf2-Anti-Oxidant System and the Cell Cycle in Breast Cancer Cells.

    Science.gov (United States)

    Peng, Chieh Yu; You, Bang Jau; Lee, Chia Lin; Wu, Yang Chang; Lin, Wen Hsin; Lu, Te Ling; Chang, Fei-Ching; Lee, Hong Zin

    2016-01-01

    4[Formula: see text]-Hydroxywithanolide E is an active component of the extract of Physalis peruviana that has been reported to exhibit antitumor effects. Although the involvement of reactive oxygen species (ROS) production and the ataxia-telangiectasia mutated protein (ATM)-dependent DNA damage signaling pathway in 4[Formula: see text]-hydroxywithanolide E-induced apoptosis of breast cancer MCF-7 cells was demonstrated in our previous study, the relationship between ROS production and the cellular defense system response in 4[Formula: see text]-hydroxywithanolide E-induced cell death requires further verification. The present study suggests that ROS play an important role in 4[Formula: see text]-hydroxywithanolide E-induced MCF-7 cell death in which anti-oxidants, such as glutathione or N-acetylcysteine, can resist the 4[Formula: see text]-hydroxywithanolide E-induced accumulation of ROS and cell death. Furthermore, N-acetylcysteine or glutathione can reverse the 4[Formula: see text]-hydroxywithanolide E-induced changes in the cell cycle distribution and the expression of cell cycle regulators. We found that the 4[Formula: see text]-hydroxywithanolide E-induced ROS accumulation was correlated with the upregulation of Nrf2 and Nrf2-downstream genes, such as antioxidative defense enzymes. In general, the activity of Nrf2 is regulated by the Ras signalling pathway. However, we demonstrated that Nrf2 was activated during 4[Formula: see text]-hydroxywithanolide E-induced MCF-7 cell death in spite of the 4[Formula: see text]-hydroxywithanolide E-induced inhibition of the Ras/Raf/ERK pathway. The activity and protein expression of superoxide dismutase and catalase were involved in the 4[Formula: see text]-hydroxywithanolide E-induced ROS production in MCF-7 cells. Furthermore, 4[Formula: see text]-hydroxywithanolide E was demonstrated to significantly reduce the sizes of the tumor nodules in the human breast cancer MDA-MB231 xenograft tumor model. PMID:27109152

  7. Early alterations on photosynthesis-related parameters in Chlamydomonas reinhardtii cells exposed to atrazine: A multiple approach study.

    Science.gov (United States)

    Esperanza, Marta; Seoane, Marta; Rioboo, Carmen; Herrero, Concepción; Cid, Ángeles

    2016-06-01

    Chlamydomonas reinhardtii cells were exposed to a sublethal concentration of the widespread herbicide atrazine for 3h. Physiological cellular parameters, such as chlorophyll a fluorescence and oxidative stress monitored by flow cytometry and pigments levels were altered in microalgal cells exposed to 0.25μM of atrazine. Furthermore, the effects of this herbicide on C. reinhardtii were explored using "omics" techniques. Transcriptomic analyses, carried out by RNA-Seq technique, displayed 9 differentially expressed genes, related to photosynthesis, between control cultures and atrazine exposed cultures. Proteomic profiles were obtained using iTRAQ tags and MALDI-MS/MS analysis, identifying important changes in the proteome during atrazine stress; 5 proteins related to photosynthesis were downexpressed. The results of these experiments advance the understanding of photosynthetic adjustments that occur during an early herbicide exposure. Inhibition of photosynthesis induced by atrazine toxicity will affect the entire physiological and biochemical states of microalgal cells. PMID:26950638

  8. Validation of the cell cycle G2 delay assay in assessing ionizing radiation sensitivity and breast cancer risk

    International Nuclear Information System (INIS)

    Genetic variations in cell cycle checkpoints and DNA repair genes are associated with prolonged cell cycle G2 delay following ionizing radiation (IR) treatment and breast cancer risk. However, different studies reported conflicting results examining the association between post-IR cell cycle delay and breast cancer risk utilizing four different parameters: cell cycle G2 delay index, %G2–M, G2/G0–G1, and (G2/G0–G1)/S. Therefore, we evaluated whether different parameters may influence study results using a data set from 118 breast cancer cases and 225 controls as well as lymphoblastoid and breast cancer cell lines with different genetic defects. Our results suggest that cell cycle G2 delay index may serve as the best parameter in assessing breast cancer risk, genetic regulation of IR-sensitivity, and mutations of ataxia telangiectasia mutated (ATM) and TP53. Cell cycle delay in 21 lymphoblastoid cell lines derived from BRCA1 mutation carriers was not different from that in controls. We also showed that IR-induced DNA-damage signaling, as measured by phosphorylation of H2AX on serine 139 (γ-H2AX) was inversely associated with cell cycle G2 delay index. In summary, the cellular responses to IR are extremely complex; mutations or genetic variations in DNA damage signaling, cell cycle checkpoints, and DNA repair contribute to cell cycle G2 delay and breast cancer risk. The cell cycle G2 delay assay characterized in this study may help identify subpopulations with elevated risk of breast cancer or susceptibility to adverse effects in normal tissue following radiotherapy

  9. Proliferation assay of mouse embryonic stem (ES) cells exposed to atmospheric-pressure plasmas at room temperature

    International Nuclear Information System (INIS)

    Proliferation assays of mouse embryonic stem (ES) cells have been performed with cell culture media exposed to atmospheric-pressure plasmas (APPs), which generate reactive species in the media at room temperature. It is found that serum in cell culture media functions as a scavenger of highly reactive species and tends to protect cells in the media against cellular damage. On the other hand, if serum is not present in a cell culture medium when it is exposed to APP, the medium becomes cytotoxic and cannot be detoxified by serum added afterwards. Plasma-induced cytotoxic media hinder proliferation of mouse ES cells and may even cause cell death. It is also shown by nuclear magnetic resonance spectroscopy that organic compounds in cell culture media are in general not significantly modified by plasma exposure. These results indicate that if there is no serum in media when they are exposed to APPs, highly reactive species (such as OH radicals) generated in the media by the APP exposure are immediately converted to less reactive species (such as H2O2), which can no longer readily react with serum that is added to the medium after plasma exposure. This study has clearly shown that it is these less reactive species, rather than highly reactive species, that make the medium cytotoxic to mouse ES cells. (paper)

  10. DNA methylation analysis using CpG microarrays is impaired in benzopyrene exposed cells

    International Nuclear Information System (INIS)

    Epigenetic alterations have emerged as a key mechanism involved in tumorigenesis. These disruptions are partly due to environmental factors that change normal DNA methylation patterns necessary for transcriptional regulation and chromatin compaction. Microarray technologies are allowing environmentally susceptible epigenetic patterns to be mapped and the precise targets of environmentally induced alterations to be identified. Previously, we observed BaP-induced epigenetic events and cell cycle disruptions in breast cancer cell lines that included time- and concentration-dependent loss of proliferation as well as sequence-specific hypo- and hypermethylation events. In this present report, we further characterized epigenetic changes in BaP-exposed MCF-7 cells. We analyzed DNA methylation on a CpG island microarray platform with over 5400 unique genomic regions. Depleted and enriched microarray targets, representative of putative DNA methylation changes, were identified across the genome; however, subsequent sodium bisulfite analyses revealed no changes in DNA methylation at a number of these loci. Instead, we found that the identification of DNA methylation changes using this restriction enzyme-based microarray approach corresponded with the regions of DNA bound by the BaP derived DNA adducts. This DNA adduct formation occurs at both methylated and unmethylated CpG dinucleotides and affects PCR amplification during sample preparation. Our data suggest that caution should be exercised when interpreting data from comparative microarray experiments that rely on enzymatic reactions. These results are relevant to genome screening approaches involving environmental exposures in which DNA adduct formation at specific nucleotide sites may bias target acquisition and compromise the correct identification of epigenetically responsive genes

  11. Comet assay in gill cells of Prochilodus lineatus exposed in vivo to cypermethrin.

    Science.gov (United States)

    Poletta, G L; Gigena, F; Loteste, A; Parma, M J; Kleinsorge, E C; Simoniello, M F

    2013-11-01

    Agricultural chemicals can induce genetic alterations on aquatic organisms that have been associated with effects on growth, reproduction and population dynamics. The evaluation of DNA damage in fish using the comet assay (CA) frequently involves the utilization of erythrocytes. However, epithelial gill cells (EGC) can be more sensitive, as they are constantly dividing and in direct contact with potentially stressing compounds from the aquatic environment. The aim of the present study was to evaluate (1) the sensitivity and suitability of epithelial gill cells of Prochilodus lineatus in response to different genotoxic agents through the application of the CA, (2) the induction of DNA damage in this cell population after in vivo exposure to cypermethrin. Baseline value of the CA damage index (DI) for EGC of juvenile P. lineatus was 144.68±5.69. Damage increased in a dose-dependent manner after in vitro exposure of EGC to methyl methanesulfonate (MMS) and H2O2, two known genotoxic agents. In vivo exposure of fish to cypermethrin induced a significant increase in DNA DI of EGC at 0.150μg/l (DI: 239.62±6.21) and 0.300μg/l (270.63±2.09) compared to control (150.25±4.38) but no effect was observed at 0.075μg/l (168.50±10.77). This study shows that EGC of this species are sensitive for the application of the CA, demonstrating DNA damage in response to alkylation (MMS), oxidative damage (H2O2), and to the insecticide cypermethryn. These data, together with our previous study on DNA damage induction on erythrocytes of this species, provides useful information for future work involving biomonitoring in regions where P. lineatus is naturally exposed to pesticides and other genotoxic agents. PMID:24267701

  12. Acute respiratory bronchiolitis: an ultrastructural and autoradiographic study of epithelial cell injury and renewal in Rhesus monkeys exposed to ozone

    International Nuclear Information System (INIS)

    The pathogenesis of acute respiratory bronchiolitis was examined in Rhesus monkeys exposed to 0.8 ppM ozone for 4 to 50 hours. Epithelial injury and renewal were qualitatively and quantitatively characterized by correlated techniques of scanning and transmission electron microscopy as well as by light-microscopic autoradiography following labeling with tritiated thymidine. Extensive degeneration and necrosis of Type 1 epithelial cells occurred on the respiratory bronchiolar wall during the initial 4 to 12 hours of exposure. Increased numbers of labeled epithelial cells were present in this region after 18 hours of exposure, and the highest labeling index (18%) was measured after 50 hours of exposure. Most (67 to 80%) of the labeled cells and all the mitotic epithelial cells (22) observed ultrastructurally were cuboidal bronchiolar epithelial cells. Of the labeled epithelial cells, 20 to 33% were Type 2 epithelial cells. After 50 hours of exposure the respiratory bronchiolar epithelium was hyperplastic. The predominant inflammatory cell in respiratory bronchiolar exudate was the alveolar macrophage. Monkeys that were exposed for 50 hours and allowed to recover in unozonized air for 7 days had incomplete resolution of respiratory bronchiolar epithelial hyperplasia. The results indicate that Type 1 epithelial cells lining respiratory bronchioles are the cell types most sensitive to injury and that both cuboidal bronchiolar epithelial cells and Type 2 epithelial cells function as stem cells in epithelial renewal

  13. Transcriptomic analysis of cultured whale skin cells exposed to hexavalent chromium [Cr(VI)].

    Science.gov (United States)

    Pabuwal, Vagmita; Boswell, Mikki; Pasquali, Amanda; Wise, Sandra S; Kumar, Suresh; Shen, Yingjia; Garcia, Tzintzuni; Lacerte, Carolyne; Wise, John Pierce; Wise, John Pierce; Warren, Wesley; Walter, Ronald B

    2013-06-15

    Hexavalent chromium Cr(VI) is known to produce cytotoxic effects in humans and is a highly toxic environmental contaminant. Interestingly, it has been shown that free ranging sperm whales (Phyester macrocephalus) may have exceedingly high levels of Cr in their skin. Also, it has been demonstrated that skin cells from whales appear more resistant to both cytotoxicity and clastogenicity upon Cr exposure compared to human cells. However, the molecular genetic mechanisms employed in whale skin cells that might lead to Cr tolerance are unknown. In an effort to understand the underlying mechanisms of Cr(VI) tolerance and to illuminate global gene expression patterns modulated by Cr, we exposed whale skin cells in culture to varying levels of Cr(VI) (i.e., 0.0, 0.5, 1.0 and 5.0 μg/cm²) followed by short read (100 bp) next generation RNA sequencing (RNA-seq). RNA-seq reads from all exposures (≈280 million reads) were pooled to generate a de novo reference transcriptome assembly. The resulting whale reference assembly had 11K contigs and an N50 of 2954 bp. Using the reads from each dose (0.0, 0.5, 1.0 and 5.0 μg/cm²) we performed RNA-seq based gene expression analysis that identified 35 up-regulated genes and 19 down-regulated genes. The experimental results suggest that low dose exposure to Cr (1.0 μg/cm²) serves to induce up-regulation of oxidative stress response genes, DNA repair genes and cell cycle regulator genes. However, at higher doses (5.0 μg/cm²) the DNA repair genes appeared down-regulated while other genes that were induced suggest the initiation of cytotoxicity. The set of genes identified that show regulatory modulation at different Cr doses provide specific candidates for further studies aimed at determination of how whales exhibit resistance to Cr toxicity and what role(s) reactive oxygen species (ROS) may play in this process. PMID:23584427

  14. Attenuation of the DNA Damage Response by Transforming Growth Factor-Beta Inhibitors Enhances Radiation Sensitivity of Non–Small-Cell Lung Cancer Cells In Vitro and In Vivo

    Energy Technology Data Exchange (ETDEWEB)

    Du, Shisuo; Bouquet, Sophie; Lo, Chen-Hao; Pellicciotta, Ilenia; Bolourchi, Shiva [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States); Parry, Renate [Varian Medical Systems, Palo Alto, California (United States); Barcellos-Hoff, Mary Helen, E-mail: mhbarcellos-hoff@nyumc.org [Department of Radiation Oncology, New York University School of Medicine, New York, New York (United States)

    2015-01-01

    Purpose: To determine whether transforming growth factor (TGF)-β inhibition increases the response to radiation therapy in human and mouse non–small-cell lung carcinoma (NSCLC) cells in vitro and in vivo. Methods and Materials: TGF-β–mediated growth response and pathway activation were examined in human NSCLC NCI-H1299, NCI-H292, and A549 cell lines and murine Lewis lung cancer (LLC) cells. Cells were treated in vitro with LY364947, a small-molecule inhibitor of the TGF-β type 1 receptor kinase, or with the pan-isoform TGF-β neutralizing monoclonal antibody 1D11 before radiation exposure. The DNA damage response was assessed by ataxia telangiectasia mutated (ATM) or Trp53 protein phosphorylation, γH2AX foci formation, or comet assay in irradiated cells. Radiation sensitivity was determined by clonogenic assay. Mice bearing syngeneic subcutaneous LLC tumors were treated with 5 fractions of 6 Gy and/or neutralizing or control antibody. Results: The NCI-H1299, A549, and LLC NSCLC cell lines pretreated with LY364947 before radiation exposure exhibited compromised DNA damage response, indicated by decreased ATM and p53 phosphorylation, reduced γH2AX foci, and increased radiosensitivity. The NCI-H292 cells were unresponsive. Transforming growth factor-β signaling inhibition in irradiated LLC cells resulted in unresolved DNA damage. Subcutaneous LLC tumors in mice treated with TGF-β neutralizing antibody exhibited fewer γH2AX foci after irradiation and significantly greater tumor growth delay in combination with fractionated radiation. Conclusions: Inhibition of TGF-β before radiation attenuated DNA damage recognition and increased radiosensitivity in most NSCLC cells in vitro and promoted radiation-induced tumor control in vivo. These data support the rationale for concurrent TGF-β inhibition and RT to provide therapeutic benefit in NSCLC.

  15. Involvement of DNA-PK and ATM in radiation- and heat-induced DNA damage recognition and apoptotic cell death

    International Nuclear Information System (INIS)

    Exposure to ionizing radiation and hyperthermia results in important biological consequences, e.g. cell death, chromosomal aberrations, mutations, and DNA strand breaks. There is good evidence that the nucleus, specifically cellular DNA, is the principal target for radiation-induced cell lethality. DNA double-strand breaks (DSBs) are considered to be the most serious type of DNA damage induced by ionizing radiation. On the other hand, verifiable mechanisms which can lead to heat-induced cell death are damage to the plasma membrane and/or inactivation of heat-labile proteins caused by protein denaturation and subsequent aggregation. Recently, several reports have suggested that DSBs can be induced after hyperthermia because heat-induced phosphorylated histone H2AX (γ-H2AX) foci formation can be observed in several mammalian cell lines. In mammalian cells, DSBs are repaired primarily through two distinct and complementary mechanisms: non-homologous end joining (NHEJ), and homologous recombination (HR) or homology-directed repair (HDR). DNA-dependent protein kinase (DNA-PK) and ataxia-telangiectasia mutated (ATM) are key players in the initiation of DSB repair and phosphorylate and/or activate many substrates, including themselves. These phosphorylated substrates have important roles in the functioning of cell cycle checkpoints and in cell death, as well as in DSB repair. Apoptotic cell death is a crucial cell suicide mechanism during development and in the defense of homeostasis. If DSBs are unrepaired or misrepaired, apoptosis is a very important system which can protect an organism against carcinogenesis. This paper reviews recently obtained results and current topics concerning the role of DNA-PK and ATM in heat- or radiation-induced apoptotic cell death. (author)

  16. Phosphorylation-Dependent Regulation of the DNA Damage Response of Adaptor Protein KIBRA in Cancer Cells.

    Science.gov (United States)

    Mavuluri, Jayadev; Beesetti, Swarnalatha; Surabhi, Rohan; Kremerskothen, Joachim; Venkatraman, Ganesh; Rayala, Suresh K

    2016-05-01

    Multifunctional adaptor proteins encompassing various protein-protein interaction domains play a central role in the DNA damage response pathway. In this report, we show that KIBRA is a physiologically interacting reversible substrate of ataxia telangiectasia mutated (ATM) kinase. We identified the site of phosphorylation in KIBRA as threonine 1006, which is embedded within the serine/threonine (S/T) Q consensus motif, by site-directed mutagenesis, and we further confirmed the same with a phospho-(S/T) Q motif-specific antibody. Results from DNA repair functional assays such as the γ-H2AX assay, pulsed-field gel electrophoresis (PFGE), Comet assay, terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, and clonogenic cell survival assay using stable overexpression clones of wild-type (wt.) KIBRA and active (T1006E) and inactive (T1006A) KIBRA phosphorylation mutants showed that T1006 phosphorylation on KIBRA is essential for optimal DNA double-strand break repair in cancer cells. Further, results from stable retroviral short hairpin RNA-mediated knockdown (KD) clones of KIBRA and KIBRA knockout (KO) model cells generated by a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system showed that depleting KIBRA levels compromised the DNA repair functions in cancer cells upon inducing DNA damage. All these phenotypic events were reversed upon reconstitution of KIBRA into cells lacking KIBRA knock-in (KI) model cells. All these results point to the fact that phosphorylated KIBRA might be functioning as a scaffolding protein/adaptor protein facilitating the platform for further recruitment of other DNA damage response factors. In summary, these data demonstrate the imperative functional role of KIBRAper se(KIBRA phosphorylation at T1006 site as a molecular switch that regulates the DNA damage response, possibly via the nonhomologous end joining [NHEJ] pathway), suggesting that KIBRA could be a potential

  17. Growth Inhibition Occurs Independently of Cell Mortality in Tomato (Solanum lycopersicum) Exposed to High Cadmium Concentrations

    Institute of Scientific and Technical Information of China (English)

    Christine Delpérée; Stanley Lutts

    2008-01-01

    In order to analyze the adaptation potential of tomato shoots to a sudden increase in Cd concentration, tomato plants (Solanum lycopersicum L. var. Ailsa Craig) were exposed under controlled environmental conditions to a high dose of this heavy metal (250 μM CdCl2>) in nutrient solution for 7 and 14 d. Both root and shoot growth was completely inhibited but all plants remained alive until the end of the treatment. Cell viability remained unaffected but the activity of the mitochondrial alternative pathway was stimulated by Cd stress at the expense of the cytochrome pathway. Cadmium concentration was higher in roots than in shoots and a decrease In the rate of net Cd translocation was noticed during the second week of stress. Cadmium decreased both leaf conductance (g1>) and chlorophyll concentration. However, the effect on net CO2 assimilation remained limited and soluble sugars accumulated in leaves. Photochemical efficiency of PSll (FvlFm) was not affected despite a decrease in the number of reaction centers and an inhibition of electron transfer to acceptors of PSII. It is concluded that tomato shoot may sustain short term exposure to high doses of cadmium despite growth inhibition. This property implies several physiological strategies linked to both avoidance and tolerance mechanisms.

  18. Natural Products Mediated Regulation of Oxidative Stress and DNA Damage in Ultraviolet Exposed Skin Cells.

    Science.gov (United States)

    Farooqi, Ammad A; Li, Ruei-Nian; Huang, Hurng-Wern; Ismail, Muhammad; Yuan, Shyng-Shiou F; Wang, Hui-Min D; Liu, Jing-Ru; Tang, Jen-Yang; Chang, Hsueh-Wei

    2015-01-01

    Data obtained through high-throughput technologies have gradually revealed that a unique stratified epithelial architecture of human skin along with the antioxidant-response pathways provided vital defensive mechanisms against UV radiation. However, it is noteworthy that skin is a major target for toxic insult by UV radiations that can alter its structure and function. Substantial fraction of information has been added into the existing pool of knowledge related to natural products mediated biological effects in UV exposed skin cells. Accumulating evidence has started to shed light on the potential of these bioactive ingredients as protective natural products in cosmetics against UV photodamage by exerting biological effects mainly through wide ranging intracellular signalling cascades of oxidative stress and modulation of miRNAs. In this review, we have summarized recently emerging scientific evidences addressing underlying mechanisms of UV induced oxidative stress and deregulation of signalling cascades and how natural products can be used tactfully to protect against UV induced harmful effects. PMID:26238680

  19. Persistent oxidative stress in human neural stem cells exposed to low fluences of charged particles

    Directory of Open Access Journals (Sweden)

    Janet E. Baulch

    2015-08-01

    Full Text Available Exposure to the space radiation environment poses risks for a range of deleterious health effects due to the unique types of radiation encountered. Galactic cosmic rays are comprised of a spectrum of highly energetic nuclei that deposit densely ionizing tracks of damage along the particle trajectory. These tracks are distinct from those generated by the more sparsely ionizing terrestrial radiations, and define the geometric distribution of the complex cellular damage that results when charged particles traverse the tissues of the body. The exquisite radiosensitivity of multipotent neural stem and progenitor cells found within the neurogenic regions of the brain predispose the central nervous system to elevated risks for radiation induced sequelae. Here we show that human neural stem cells (hNSC exposed to different charged particles at space relevant fluences exhibit significant and persistent oxidative stress. Radiation induced oxidative stress was found to be most dependent on total dose rather than on the linear energy transfer of the incident particle. The use of redox sensitive fluorogenic dyes possessing relative specificity for hydroxyl radicals, peroxynitrite, nitric oxide (NO and mitochondrial superoxide confirmed that most irradiation paradigms elevated reactive oxygen and nitrogen species (ROS and RNS, respectively in hNSC over a 1 week interval following exposure. Nitric oxide synthase (NOS was not the major source of elevated nitric oxides, as the use of NOS inhibitors had little effect on NO dependent fluorescence. Our data provide extensive evidence for the capability of low doses of charged particles to elicit marked changes in the metabolic profile of irradiated hNSC. Radiation induced changes in redox state may render the brain more susceptible to the development of neurocognitive deficits that could affect an astronaut’s ability to perform complex tasks during extended missions in deep space.

  20. Oxidative stress response in neural stem cells exposed to different superparamagnetic iron oxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Pongrac IM

    2016-04-01

    Full Text Available Igor M Pongrac,1 Ivan Pavičić,2 Mirta Milić,2 Lada Brkič Ahmed,1 Michal Babič,3 Daniel Horák,3 Ivana Vinković Vrček,2 Srećko Gajović1 1School of Medicine, Croatian Institute for Brain Research, University of Zagreb, 2Institute for Medical Research and Occupational Health, Zagreb, Croatia; 3Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic Abstract: Biocompatibility, safety, and risk assessments of superparamagnetic iron oxide nanoparticles (SPIONs are of the highest priority in researching their application in biomedicine. One improvement in the biological properties of SPIONs may be achieved by different functionalization and surface modifications. This study aims to investigate how a different surface functionalization of SPIONs – uncoated, coated with D-mannose, or coated with poly-L-lysine – affects biocompatibility. We sought to investigate murine neural stem cells (NSCs as important model system for regenerative medicine. To reveal the possible mechanism of toxicity of SPIONs on NSCs, levels of reactive oxygen species, intracellular glutathione, mitochondrial membrane potential, cell-membrane potential, DNA damage, and activities of SOD and GPx were examined. Even in cases where reactive oxygen species levels were significantly lowered in NSCs exposed to SPIONs, we found depleted intracellular glutathione levels, altered activities of SOD and GPx, hyperpolarization of the mitochondrial membrane, dissipated cell-membrane potential, and increased DNA damage, irrespective of the surface coating applied for SPION stabilization. Although surface coating should prevent the toxic effects of SPIONs, our results showed that all of the tested SPION types affected the NSCs similarly, indicating that mitochondrial homeostasis is their major cellular target. Despite the claimed biomedical benefits of SPIONs, the refined determination of their effects on various cellular functions

  1. B cells play key roles in th2-type airway immune responses in mice exposed to natural airborne allergens.

    Directory of Open Access Journals (Sweden)

    Li Yin Drake

    Full Text Available Humans are frequently exposed to various airborne allergens. In addition to producing antibodies, B cells participate in immune responses via various mechanisms. The roles of B cells in allergic airway inflammation and asthma have been controversial. We examined the functional importance of B cells in a mouse model of asthma, in which mice were exposed repeatedly to common airborne allergens. Naïve wild-type BALB/c mice or B cell-deficient JH-/- mice were exposed intranasally to a cocktail of allergen extracts, including Alternaria, Aspergillus, and house dust mite, every other day for two weeks. Ovalbumin was included in the cocktail to monitor the T cell immune response. Airway inflammation, lung pathology, and airway reactivity were analyzed. The airway exposure of naïve wild type mice to airborne allergens induced robust eosinophilic airway inflammation, increased the levels of Th2 cytokines and chemokines in the lung, and increased the reactivity to inhaled methacholine. These pathological changes and immune responses were attenuated in B cell-deficient JH-/- mice. The allergen-induced expansion of CD4+ T cells was impaired in the lungs and draining lymph nodes of JH-/- mice. Furthermore, lymphocytes from JH-/- mice failed to produce Th2 cytokines in response to ovalbumin re-stimulation in vitro. Our results suggest that B cells are required for the optimal development of Th2-type immune responses and airway inflammation when exposed to common airborne allergens. The therapeutic targeting of B cells may be beneficial to treat asthma in certain patients.

  2. Effect of silencing of ATM expression by siRNA on radiosensitivity of human lung adenocarcinoma A549 cells

    International Nuclear Information System (INIS)

    Objective: To investigate the effect of silencing of ataxia-telangiectasia mutated (ATM) expression by plasmid-mediated RNA interference on the radiosensitivity of human lung adenocarcinoma A549 cells. Methods: Eukaryotic expression plasmid containing ATM small interfering RNA (siRNA) (pSilencer2.1-ATM), as well as pSilencer2.1-nonspecific, was constructed.Lung adenocarcinoma A549 cells were divided into positive group, negative group,and control group to be transfected with pSilencer2.1-ATM, pSilencer2.1-nonspecific, and no plasmid, respectively. The mRNA and protein expression of ATM was measured by RT-PCR and Western blot, respectively. The change in cell radiosensitivity was observed by colony-forming assay. Cell cycle and cell apoptosis were analyzed by flow cytometry. Results: The eukaryotic expression plasmid containing ATM siRNA was successfully constructed. The RT-PCR and Western blot demonstrated that the expression of ATM was down-regulated in the positive group. The sensitization enhancement ratios (D0 ratios) for the positive group and negative group were 1.50 and 1.01, respectively. The flow cytometry revealed that the proportions of A549 cells in G1 and G2/M phases were significantly lower in the positive group than in the control group (51.27% vs 61.85%, P = 0.012; 6.34% vs 10.91%, P = 0.008) and that the apoptosis rate was significantly higher in the positive group than in the control group and negative group (49.31% vs 13.58%, P = 0.000; 49.31% vs 13.17%, P = 0.000). Conclusions: Silencing of ATM expression may increase the radiosensitivity of human lung adenocarcinoma A549 cells, probably by affecting the cell cycle and promoting cell apoptosis. (authors)

  3. Induction of sister-chromatid exchanges in ICR 2A frog cells exposed to 254 nm UV wavelengths

    International Nuclear Information System (INIS)

    Exposure of ICR 2A frog cells to 254 nm UV induced the formation of sister-chromatid exchanges (SCEs) in a fluence-dependent manner. Cells were also exposed to the UV produced by a fluorescent sunlamp that was filtered through 8C Mylar in order to simulate the mid-UV (290-320 nm) portion of sunlight reaching the earth's surface. In this instance, SCEs were induced in a linear fashion at low fluences but reached a plateau at a low level of induced SCEs. In addition, pretreatment of cells with the solar UV followed by exposure to 254 nm UV resulted in a significantly lower level of SCEs than in cells exposed to 254 nm UV alone. (author)

  4. The membrane potential of characean cells exposed to amplitude-modulated, low-power 147-MHz radiation

    Energy Technology Data Exchange (ETDEWEB)

    Brunkard, K.M.; Pickard, W.F.

    1984-01-01

    The membrane potential of isolated cells of Chara braunii or Nitella flexilis was monitored while the cells were exposed, at nominal power densities from 2 to 1,000 W/m2, to 147-MHz radiation amplitude modulated at frequencies from 4 to 64 Hz. Phase-sensitive detection was used to seek radiation-correlated changes in the membrane potential, and none were apparent under any of the conditions used in this investigation.

  5. Analysis of Pseudomonas aeruginosa Cell Envelope Proteome by Capture of Surface-Exposed Proteins on Activated Magnetic Nanoparticles

    OpenAIRE

    Davide Vecchietti; Dario Di Silvestre; Matteo Miriani; Francesco Bonomi; Mauro Marengo; Alessandra Bragonzi; Lara Cova; Eleonora Franceschi; Pierluigi Mauri; Giovanni Bertoni

    2012-01-01

    We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT) for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedde...

  6. ATM-deficient human fibroblast cells are resistant to low levels of DNA double-strand break induced apoptosis and subsequently undergo drug-induced premature senescence

    International Nuclear Information System (INIS)

    Highlights: ► A-T cells were not hypersensitive to low levels of DNA DSBs. ► A-T cells have enhanced Akt but defect in activation of p53 and apoptotic proteins. ► A-T cells underwent premature senescence after DNA damage accumulated. ► Chemotherapeutic effect in cancer therapy may be associated with premature senescence. -- Abstract: DNA DSBs are induced by IR or radiomimetic drugs such as doxorubicin. It has been indicated that cells from ataxia-telangiectasia patients are highly sensitive to radiation due to defects in DNA repair, but whether they have impairment in apoptosis has not been fully elucidated. A-T cells showed increased sensitivity to high levels of DNA damage, however, they were more resistant to low doses. Normal cells treated with combination of KU55933, a specific ATM kinase inhibitor, and doxorubicin showed increased resistance as they do in a similar manner to A-T cells. A-T cells have higher viability but more DNA breaks, in addition, the activations of p53 and apoptotic proteins (Bax and caspase-3) were deficient, but Akt expression was enhanced. A-T cells subsequently underwent premature senescence after treatment with a low dose of doxorubicin, which was confirmed by G2 accumulation, senescent morphology, and SA-β-gal positive until 15 days repair incubation. Finally, A-T cells are radio-resistant at low doses due to its defectiveness in detecting DNA damage and apoptosis, but the accumulation of DNA damage leads cells to premature senescence.

  7. ATM-deficient human fibroblast cells are resistant to low levels of DNA double-strand break induced apoptosis and subsequently undergo drug-induced premature senescence

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jun; Jo, Yong Hwa; Cho, Chang Hoon; Choe, Wonchae; Kang, Insug; Baik, Hyung Hwan [Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); Yoon, Kyung-Sik, E-mail: sky9999@khu.ac.kr [Department of Biochemistry and Molecular Biology, School of Medicine, Kyung Hee University, 26 Kyunghee-daero, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer A-T cells were not hypersensitive to low levels of DNA DSBs. Black-Right-Pointing-Pointer A-T cells have enhanced Akt but defect in activation of p53 and apoptotic proteins. Black-Right-Pointing-Pointer A-T cells underwent premature senescence after DNA damage accumulated. Black-Right-Pointing-Pointer Chemotherapeutic effect in cancer therapy may be associated with premature senescence. -- Abstract: DNA DSBs are induced by IR or radiomimetic drugs such as doxorubicin. It has been indicated that cells from ataxia-telangiectasia patients are highly sensitive to radiation due to defects in DNA repair, but whether they have impairment in apoptosis has not been fully elucidated. A-T cells showed increased sensitivity to high levels of DNA damage, however, they were more resistant to low doses. Normal cells treated with combination of KU55933, a specific ATM kinase inhibitor, and doxorubicin showed increased resistance as they do in a similar manner to A-T cells. A-T cells have higher viability but more DNA breaks, in addition, the activations of p53 and apoptotic proteins (Bax and caspase-3) were deficient, but Akt expression was enhanced. A-T cells subsequently underwent premature senescence after treatment with a low dose of doxorubicin, which was confirmed by G2 accumulation, senescent morphology, and SA-{beta}-gal positive until 15 days repair incubation. Finally, A-T cells are radio-resistant at low doses due to its defectiveness in detecting DNA damage and apoptosis, but the accumulation of DNA damage leads cells to premature senescence.

  8. Uncovering surface-exposed antigens of Lactobacillus rhamnosus by cell shaving proteomics and two-dimensional immunoblotting.

    Science.gov (United States)

    Espino, Eva; Koskenniemi, Kerttu; Mato-Rodriguez, Lourdes; Nyman, Tuula A; Reunanen, Justus; Koponen, Johanna; Öhman, Tiina; Siljamäki, Pia; Alatossava, Tapani; Varmanen, Pekka; Savijoki, Kirsi

    2015-02-01

    The present study reports the identification and comparison of all expressed cell-surface exposed proteins from the well-known probiotic L. rhamnosus GG and a related dairy strain, Lc705. To obtain this information, the cell-surface bound proteins were released from intact cells by trypsin shaving under hypertonic conditions with and without DTT. Liquid chromatography tandem mass spectrometry (LC-MS/MS) analyses of the purified peptides identified a total of 102 and 198 individual proteins from GG and Lc705, respectively. Comparison of both data sets suggested that the Msp-type antigens (Msp1, Msp2) and the serine protease HtrA were uniquely exposed at the cell surface of GG, whereas the Lc705-specific proteins included lactocepin and a wider range of different moonlighting proteins. ImmunoEM analyses with the GG and Lc705 antibodies suggested that the whole-cell immunization yielded antibodies toward surface-bound proteins and proteins that were secreted or released from the cell-surface. One of the detected antigens was a pilus-like structure on the surface of GG cells, which was not detected with Lc705 antibodies. Further 2-DE immunoblotting analysis of GG proteins with both L. rhamnosus antisera revealed that majority of the detected antigens were moonlighting proteins with potential roles in adhesion, pathogen exclusion or immune stimulation. The present study provides the first catalog of surface-exposed proteins from lactobacilli and highlights the importance of the specifically exposed moonlighting proteins for adaptation and probiotic functions of L. rhamnosus. PMID:25531588

  9. BIGEL analysis of gene expression in HL60 cells exposed to X rays or 60 Hz magnetic fields

    Science.gov (United States)

    Balcer-Kubiczek, E. K.; Zhang, X. F.; Han, L. H.; Harrison, G. H.; Davis, C. C.; Zhou, X. J.; Ioffe, V.; McCready, W. A.; Abraham, J. M.; Meltzer, S. J.

    1998-01-01

    We screened a panel of 1,920 randomly selected cDNAs to discover genes that are differentially expressed in HL60 cells exposed to 60 Hz magnetic fields (2 mT) or X rays (5 Gy) compared to unexposed cells. Identification of these clones was accomplished using our two-gel cDNA library screening method (BIGEL). Eighteen cDNAs differentially expressed in X-irradiated compared to control HL60 cells were recovered from a panel of 1,920 clones. Differential expression in experimental compared to control cells was confirmed independently by Northern blotting of paired total RNA samples hybridized to each of the 18 clone-specific cDNA probes. DNA sequencing revealed that 15 of the 18 cDNA clones produced matches with the database for genes related to cell growth, protein synthesis, energy metabolism, oxidative stress or apoptosis (including MYC, neuroleukin, copper zinc-dependent superoxide dismutase, TC4 RAS-like protein, peptide elongation factor 1alpha, BNIP3, GATA3, NF45, cytochrome c oxidase II and triosephosphate isomerase mRNAs). In contrast, BIGEL analysis of the same 1,920 cDNAs revealed no differences greater than 1.5-fold in expression levels in magnetic-field compared to sham-exposed cells. Magnetic-field-exposed and control samples were analyzed further for the presence of mRNA encoding X-ray-responsive genes by hybridization of the 18 specific cDNA probes to RNA from exposed and control HL60 cells. Our results suggest that differential gene expression is induced in approximately 1% of a random pool of cDNAs by ionizing radiation but not by 60 Hz magnetic fields under the present experimental conditions.

  10. Relationship of CD86 surface marker expression and cytotoxicity on dendritic cells exposed to chemical allergen

    International Nuclear Information System (INIS)

    Human peripheral blood-derived dendritic cells (DC) respond to a variety of chemical allergens by up-regulating expression of the co-stimulatory molecule CD86. It has been postulated that this measure might provide the basis for an in vitro alternative approach for the identification of skin sensitizing chemicals. We recently reported that DC, exposed in culture to the highest non-cytotoxic concentrations of various chemical allergens, displayed marginal up-regulation of membrane CD86 expression; the interpretation being that such changes were insufficiently sensitive for the purposes of hazard identification. For the work presented here, immature DC were derived from human monocytes and treated with the chemical allergens 2,4-dinitrobenzenesulfonic acid (DNBS), nickel sulfate (NiSO4), p-phenylenediamine (PPD), Bandrowski's base (BB), hydroquinone (HQ) and propyl gallate (PG) for 48 h at concentrations which induced both no to slight to moderate cytotoxicity. For comparison, DC were treated with the irritants sodium dodecyl sulfate (SDS), benzoic acid (BA), and benzalkonium chloride (BZC) at concentrations resulting in comparable levels of cytotoxicity. CD86 expression, as measured by flow cytometry, was consistently up-regulated (ranging from 162 to 386% control) on DC treated with concentrations of chemical allergens that induced approximately 10-15% cytotoxicity. The irritants BA and BZC did not induce up-regulation of CD86 expression when tested at concentrations that induced similar levels of cytotoxicity. SDS, however, up-regulated CD86 expression to 125-138% of control in 2/4 preparations when tested at concentrations which induced similar toxicity. Our results confirm that chemical allergens up-regulate CD86 expression on blood-derived DC and illustrate further that up-regulation of CD86 surface marker expression is more robust when DC are treated with concentrations of chemical allergen that induce slight to moderate cytotoxicity

  11. Exposed hydrophobic residues in human immunodeficiency virus type 1 Vpr helix-1 are important for cell cycle arrest and cell death.

    Directory of Open Access Journals (Sweden)

    R Anthony Barnitz

    Full Text Available The human immunodeficiency virus type 1 (HIV-1 accessory protein viral protein R (Vpr is a major determinant for virus-induced G2/M cell cycle arrest and cytopathicity. Vpr is thought to perform these functions through the interaction with partner proteins. The NMR structure of Vpr revealed solvent exposed hydrophobic amino acids along helices 1 and 3 of Vpr, which could be putative protein binding domains. We previously showed that the hydrophobic patch along helix-3 was important for G2/M blockade and cytopathicity. Mutations of the exposed hydrophobic residues along helix-1 were found to reduce Vpr-induced cell cycle arrest and cell death as well. The levels of toxicity during virion delivery of Vpr correlated with G2/M arrest. Thus, the exposed hydrophobic amino acids in the amino-terminal helix-1 are important for the cell cycle arrest and cytopathicity functions of Vpr.

  12. Accumulation of apoptosis-insensitive human bone marrow-mesenchymal stromal cells after long-term expansion.

    Science.gov (United States)

    Jeong, Sin-Gu; Cho, Goang-Won

    2016-07-01

    Cells undergo replicative senescence during in vitro expansion, which is induced by the accumulation of cellular damage caused by excessive reactive oxygen species. In this study, we investigated whether long-term-cultured human bone marrow mesenchymal stromal cells (MSCs) are insensitive to apoptotic stimulation. To examine this, we established replicative senescent cells from long-term cultures of human bone marrow MSCs. Senescent cells were identified based on declining population doublings, increased expression of senescence markers p16 and p53 and increased senescence-associated β-gal activity. In cell viability assays, replicative senescent MSCs in late passages (i.e. 15-19 passages) resisted damage induced by oxidative stress more than those in early passages did (i.e. 7-10 passages). This resistance occurred via caspase-9 and caspase-3 rather than via caspase-8. The senescent cells are gradually accumulated during long-term expansion. The oxidative stress-sensitive proteins ataxia-telangiectasia mutated and p53 were phosphorylated, and the expression of apoptosis molecules Bax increased, and Bcl-2 decreased in early passage MSCs; however, the expression of the apoptotic molecules did less change in response to apoptotic stimulation in late-passage MSCs, suggesting that the intrinsic apoptotic signalling pathway was not induced by oxidative stress in long-term-cultured MSCs. Based on these results, we propose that some replicative senescent cells may avoid apoptosis signalling via impairment of signalling molecules and accumulation during long-term expansion. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27212655

  13. Upregulation of TRPM7 augments cell proliferation and interleukin-8 release in airway smooth muscle cells of rats exposed to cigarette smoke.

    Science.gov (United States)

    Lin, Xiaoling; Yang, Cheng; Huang, Linjie; Chen, Ming; Shi, Jianting; Ouyang, Lihua; Tang, Tiantian; Zhang, Wei; Li, Yiqun; Liang, Ruiyun; Jiang, Shanping

    2016-06-01

    Proliferation and synthetic function (i.e. the capacity to release numerous chemokines and cytokines) of airway smooth muscle cells (ASMCs) are important in airway remodeling induced by cigarette smoke exposure. However, the molecular mechanism has not been clarified. Transient receptor potential cation channel subfamily M member 7 (TRPM7) is expressed ubiquitously and is crucial for the cellular physiological function of many cell types. The present study aimed to detect the expression of TRPM7 in ASMCs from smoke‑exposed rats and determine the importance of TRPM7 in proliferation and interleukin‑8 (IL‑8) release. ASMCs were isolated and cultured from smoke‑exposed rats. Expression levels of TRPM7 were determined by reverse transcription‑polymerase chain reaction, western blot analysis and immunofluorescence. TRPM7 was silenced with TRPM7‑short hairpin RNA lentivirus vector. DNA synthesis, cell number and IL‑8 release of ASMCs induced by cigarette smoke extract (CSE) and tumor necrosis factor‑α (TNF‑α) were assessed using [3H]-thymidine incorporation assay, hemocytometer and enzyme‑linked immunosorbent assay, respectively. It was determined that mRNA and protein expression levels of TRPM7 were increased in ASMCs from smoke‑exposed rats. Stimulation with CSE or TNF‑α elevated DNA synthesis, cell number and IL‑8 release were more marked in ASMCs from smoke‑exposed rats. Silencing of TRPM7 reduced DNA synthesis, cell number and IL‑8 release induced by CSE or TNF‑α in ASMCs from smoke-exposed rats. In conclusion, expression of TRPM7 increased significantly in ASMCs from smoke‑exposed rats and the upregulation of TRPM7 led to augmented cell proliferation and IL-8 release in ASMCs from rats exposed to cigarette smoke. PMID:27108806

  14. Incorporation of tritiated thymidine by epithelial and interstitial cells in bronchiolar-alveolar regions of asbestos-exposed rats

    International Nuclear Information System (INIS)

    Inhaled asbestos causes progressive interstitial lung disease. The authors have performed a series of studies to elucidate early pathogenetic events at sites of fiber deposition in asbestos-exposed rats. This study reports that a single 5-hour exposure to chrysotile asbestos induces significant increases in incorporation of tritiated thymidine (3HTdR) into nuclei of epithelial and interstitial cells of bronchiolar-alveolar regions. No cell populations in air-exposed or carbonyl iron-exposed control animals exhibited more than 1% labeling at any point in time. Immediately after the 5-hour asbestos exposure, incorporation was normal. By 19 hours after exposure there was a significant increase in incorporation of 3HTdR, particularly by Type II epithelial cells of the first alveolar duct bifurcations. The greatest increase in degree of incorporation (up to 18-fold) was observed 24 hours after exposure, and increased percentages of 3HTdR-labeled cells were maintained through the 48 hours postexposure period. Normal labeling was present by 8 days after exposure, and this level remained through the 1-month period studied. This apparent mitogenic response correlates with increased numbers of bronchiolar-alveolar epithelial and interstitial cells demonstrated by ultrastructural morphometry in correlative studies. The authors speculate that the incorporation of 3HTdR could be induced by the direct effects of inhaled fibers or by mitogenic factors released from macrophages attracted to the inhaled asbestos

  15. Increase in DNA damage in lymphocytes and micronucleus frequency in buccal cells in silica-exposed workers

    Directory of Open Access Journals (Sweden)

    Ajanta Halder

    2012-01-01

    Full Text Available The alkaline single cell gel electrophoresis (comet assay was applied to study the genotoxic properties of silica in human peripheral blood lymphocytes (PBL. The study was designed to evaluate the DNA damage of lymphocytes and the end points like micronuclei from buccal smears in a group of 45 workers, occupationally exposed to silica, from small mines and stone quarries. The results were compared to 20 sex and age matched normal individuals. There was a statistically significant difference in the damage levels between the exposed group and the control groups. The types of damages (type I -type 1V were used to measure the DNA damage. The numbers of micronuclei were higher in the silica-exposed population. The present study suggests that the silica exposure can induce lymphocyte DNA damage and produces significant variation of micronuclei in buccal smear.

  16. Comparison of hematological alterations and markers of B-cell activation in workers exposed to benzene, formaldehyde and trichloroethylene.

    Science.gov (United States)

    Bassig, Bryan A; Zhang, Luoping; Vermeulen, Roel; Tang, Xiaojiang; Li, Guilan; Hu, Wei; Guo, Weihong; Purdue, Mark P; Yin, Songnian; Rappaport, Stephen M; Shen, Min; Ji, Zhiying; Qiu, Chuangyi; Ge, Yichen; Hosgood, H Dean; Reiss, Boris; Wu, Banghua; Xie, Yuxuan; Li, Laiyu; Yue, Fei; Freeman, Laura E Beane; Blair, Aaron; Hayes, Richard B; Huang, Hanlin; Smith, Martyn T; Rothman, Nathaniel; Lan, Qing

    2016-07-01

    Benzene, formaldehyde (FA) and trichloroethylene (TCE) are ubiquitous chemicals in workplaces and the general environment. Benzene is an established myeloid leukemogen and probable lymphomagen. FA is classified as a myeloid leukemogen but has not been associated with non-Hodgkin lymphoma (NHL), whereas TCE has been associated with NHL but not myeloid leukemia. Epidemiologic associations between FA and myeloid leukemia, and between benzene, TCE and NHL are, however, still debated. Previously, we showed that these chemicals are associated with hematotoxicity in cross-sectional studies of factory workers in China, which included extensive personal monitoring and biological sample collection. Here, we compare and contrast patterns of hematotoxicity, monosomy 7 in myeloid progenitor cells (MPCs), and B-cell activation biomarkers across these studies to further evaluate possible mechanisms of action and consistency of effects with observed hematologic cancer risks. Workers exposed to benzene or FA, but not TCE, showed declines in cell types derived from MPCs, including granulocytes and platelets. Alterations in lymphoid cell types, including B cells and CD4+ T cells, and B-cell activation markers were apparent in workers exposed to benzene or TCE. Given that alterations in myeloid and lymphoid cell types are associated with hematological malignancies, our data provide biologic insight into the epidemiological evidence linking benzene and FA exposure with myeloid leukemia risk, and TCE and benzene exposure with NHL risk. PMID:27207665

  17. PTEN enhances G2/M arrest in etoposide-treated MCF‑7 cells through activation of the ATM pathway.

    Science.gov (United States)

    Zhang, Ruopeng; Zhu, Li; Zhang, Lirong; Xu, Anli; Li, Zhengwei; Xu, Yijuan; He, Pei; Wu, Maoqing; Wei, Fengxiang; Wang, Chenhong

    2016-05-01

    As an effective tumor suppressor, phosphatase and tensin homolog (PTEN) has attracted the increased attention of scientists. Recent studies have shown that PTEN plays unique roles in the DNA damage response (DDR) and can interact with the Chk1 pathway. However, little is known about how PTEN contributes to DDR through the ATM-Chk2 pathway. It is well-known that etoposide induces G2/M arrest in a variety of cell lines, including MCF-7 cells. The DNA damage-induced G2/M arrest results from the activation of protein kinase ataxia telangiectasia mutated (ATM), followed by the activation of Chk2 that subsequently inactivates CDC25C, resulting in G2/M arrest. In the present study, we assessed the contribution of PTEN to the etoposide-induced G2/M cell cycle arrest. PTEN was knocked down in MCF-7 cells by specific shRNA, and the effects of PTEN on the ATM-Chk2 pathway were investigated through various approaches. The results showed that knockdown of PTEN strongly antagonized ATM activation in response to etoposide treatment, and thereby reduced the phosphorylation level of ATM substrates, including H2AX, P53 and Chk2. Furthermore, depletion of PTEN reduced the etoposide-induced phosphorylation of CDC25C and strikingly compromised etoposide-induced G2/M arrest in the MCF-7 cells. Altogether, we demonstrated that PTEN plays a unique role in etoposide-induced G2/M arrest by facilitating the activation of the ATM pathway, and PTEN was required for the proper activation of checkpoints in response to DNA damage in MCF-7 cells. PMID:26986476

  18. Gene expression profiling and pathway analysis of human bronchial epithelial cells exposed to airborne particulate matter collected from Saudi Arabia

    International Nuclear Information System (INIS)

    Epidemiological studies have established a positive correlation between human mortality and increased concentration of airborne particulate matters (PM). However, the mechanisms underlying PM related human diseases, as well as the molecules and pathways mediating the cellular response to PM, are not fully understood. This study aims to investigate the global gene expression changes in human cells exposed to PM10 and to identify genes and pathways that may contribute to PM related adverse health effects. Human bronchial epithelial cells were exposed to PM10 collected from Saudi Arabia for 1 or 4 days, and whole transcript expression was profiled using the GeneChip human gene 1.0 ST array. A total of 140 and 230 genes were identified that significantly changed more than 1.5 fold after PM10 exposure for 1 or 4 days, respectively. Ingenuity Pathway Analysis revealed that different exposure durations triggered distinct pathways. Genes involved in NRF2-mediated response to oxidative stress were up-regulated after 1 day exposure. In contrast, cells exposed for 4 days exhibited significant changes in genes related to cholesterol and lipid synthesis pathways. These observed changes in cellular oxidative stress and lipid synthesis might contribute to PM related respiratory and cardiovascular disease. -- Highlights: ► PM exposure modulated gene expression and associated pathways in BEAS-2B cells. ► One-day exposure to PM induced genes involved in responding to oxidative stress. ► 4-day exposure to PM changed genes associated to cholesterol and lipid synthesis.

  19. Design and synthesis of pyrrolobenzodiazepine-gallic hybrid agents as p53-dependent and -independent apoptogenic signaling in melanoma cells.

    Science.gov (United States)

    Chou, Yu-Wei; Senadi, Gopal Chandru; Chen, Chung-Yu; Kuo, Kung-Kai; Lin, Ying-Ting; Wang, Jeh-Jeng; Lee, Jia-Hau; Wang, Ya-Ching; Hu, Wan-Ping

    2016-02-15

    A new class of pyrrolo[2,1-c][1,4]benzodiazepine-Gallic hybrid agents (PBD-GA) conjugated through alkyl spacers has been designed and synthesized. The combination of these two core pharmacophores with modification in the C-8 position of the PBD ring with alkyl spacers afforded oxygen-tethered compounds 5a-5d and amide-tethered analogues 11a-11d with improved anticancer activity for two melanoma cell lines, A375 and RPMI7951, differing in their p53 status. The agents 5a-5d were cytotoxic in melanoma compared to agents 11a-11d. In particular, compounds 5b and 5c were found to possess the most potent activity compared with other hybrid agents and were proved with the help of quantitative structure activity relationship studies (QSAR). These PBD conjugates caused S phase arrest for the A375 cell line via increased reactive oxygen species (ROS) generation, deoxyribonucleic acid (DNA) damage, ataxia telangiectasia mutated (ATM)/ATM-Rad3-related (ATR) and checkpoint kinases 1 (Chk1) activation. Moreover, the PBD-GA induced A375 apoptotic cell death followed through p53 (ATM downstream target) increase, B-cell leukemia-xL (Bcl-xL) and mitochondrial membrane potential (ΔΨmt) decrease, cytochrome c release, and caspase-3/Poly Adp Ribose Polymerase (PARP) cleavage. On the other hand, mutant p53 RPMI7951 cell death occurred by PBD-GA-mediated mitochondria- and caspase-dependent pathways via lysosomal membrane permeabilization (LMP), but not through p53 signaling. Finally, compound 5b was shown to reduce murine melanoma size in a mouse model. These results suggest that the PBD-GA could be used as a useful chemotherapeutic agent in melanoma with activated p53 or mutant p53. PMID:26756315

  20. Sophoridinol derivative 05D induces tumor cells apoptosis by topoisomerase1-mediated DNA breakage

    Directory of Open Access Journals (Sweden)

    Zhao W

    2016-05-01

    Full Text Available Wuli Zhao, Caixia Zhang, Chongwen Bi, Cheng Ye, Danqing Song, Xiujun Liu, Rongguang Shao Key Laboratory of Antibiotic Bioengineering, Ministry of Health, Laboratory of Oncology, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, People’s Republic of China Abstract: Sophoridine is a quinolizidine natural product of Sophora alopecuroides and has been applied for treatment of malignant trophoblastic tumors. Although characterized by low toxicity, the limited-spectrum antitumor activity hinders its further applications. 05D, a derivative of sophoridine, exhibits a better anticancer activity on diverse cancer cells, including solid tumors, and hematologic malignancy. It could inhibit topoisomerase 1 (top1 activity by stabilizing DNA–top1 complex and induce mitochondria-mediated apoptosis by promoting DNA single- and double-strand breakage mediated by top1. Also, 05D induced HCT116 cells arrest at G1 phase by inactivating CDK2/CDK4–Rb–E2F and cyclinD1–CDK4–p21 checkpoint signal pathways. 05D suppressed the ataxia telangiectasia mutated (ATM and ATM and Rad3-related (ATR activation and decreased 53BP level, which contributed to DNA damage repair, suggesting that the novel compound 05D might be helpful to improve the antitumor activity of DNA damaging agent by repressing ATM and ATR activation and 53BP level. In addition, the priorities in molecular traits and druggability, such as a simple structure and formulation for oral administration, further prove 05D to be a promising targeting topoisomerase agent. Keywords: topoisomerase inhibitor, topoisomerase 1, DNA breakage, sophoridinol, anticancer, apoptosis, cell cycle

  1. ATM-Dependent Hyper-Radiosensitivity in Mammalian Cells Irradiated by Heavy Ions

    International Nuclear Information System (INIS)

    Purpose: Low-dose hyper-radiosensitivity (HRS) and the later appearing radioresistance (termed induced radioresistance [IRR]) was mainly studied in low linear energy transfer (LET) radiation with survival observation. The aim of this study was to find out whether equivalent hypersensitivity occurred in high LET radiation, and the roles of ataxia telangiectasia mutated (ATM) kinase. Methods and Materials: Survival and mutation were measured by clonogenic assay and HPRT mutation assay. ATM Ser1981 activation was detected by Western blotting and immunofluorescent staining. Pretreatment of specific ATM inhibitor (10 μM KU55933) and activator (20 μg/mL chloroquine) before carbon radiation were adopted to explore the involvement of ATM. The roles of ATM were also investigated in its G2/M checkpoint function with histone H3 phosphorylation analysis and flow cytometric assay, and DNA double strand break (DSB) repair function measured using γ-H2AX foci assay. Results: HRS/IRR was observed with survival and mutation in normal human skin fibroblast cells by carbon ions, while impaired in cells with intrinsic ATM deficiency or normal cells modified with specific ATM activator or inhibitor before irradiation. The dose-response pattern of ATM kinase activation was concordant with the transition from HRS to IRR. The ATM-dependent 'early' G2 checkpoint arrest and DNA DSB repair efficiency could explain the difference between HRS and IRR. Conclusions: These data demonstrate that the HRS/IRR by carbon ion radiation is an ATM-dependent phenomenon in the cellular response to DNA damage.

  2. Nestin-expressing cells in the developing, mature and noise-exposed cochlear epithelium

    OpenAIRE

    Watanabe, Reiko; Morell, Maria H.; Miller, Josef M.; Kanicki, Ariane; O'Shea, K. Sue; Altschuler, Richard A.; Raphael, Yehoash

    2011-01-01

    The auditory sensory epithelium in non-mammalian vertebrates can replace lost hair cells by transdifferentiation of supporting cells, but this regenerative ability is lost in the mammalian cochlea. Future cell-based treatment of hearing loss may depend on stem cell transplantation or on transdifferentiation of endogenous cells in the cochlea. For both approaches, identification of cells with stem cell features within the mature cochlea may be useful. Here we use a Nestin-β-gal mouse to examin...

  3. Phenotypic malignant changes and untargeted lipidomic analysis of long-term exposed prostate cancer cells to endocrine disruptors

    Energy Technology Data Exchange (ETDEWEB)

    Bedia, Carmen, E-mail: carmen.bedia@idaea.csic.es; Dalmau, Núria, E-mail: nuria.dalmau@idaea.csic.es; Jaumot, Joaquim, E-mail: joaquim.jaumot@idaea.csic.es; Tauler, Romà, E-mail: roma.tauler@idaea.csic.es

    2015-07-15

    Endocrine disruptors (EDs) are a class of environmental toxic molecules able to interfere with the normal hormone metabolism. Numerous studies involve EDs exposure to initiation and development of cancers, including prostate cancer. In this work, three different EDs (aldrin, aroclor 1254 and chlorpyrifos (CPF)) were investigated as potential inducers of a malignant phenotype in DU145 prostate cancer cells after a chronic exposure. Epithelial to mesenchymal transition (EMT) induction, proliferation, migration, colony formation and release of metalloproteinase 2 (MMP-2) were analyzed in 50-day exposed cells to the selected EDs. As a result, aldrin and CPF exposure led to an EMT induction (loss of 16% and 14% of E-cadherin levels, respectively, compared to the unexposed cells). Aroclor and CPF presented an increased migration (134% and 126%, respectively), colony formation (204% and 144%, respectively) and MMP-2 release (137% in both cases) compared to the unexposed cells. An untargeted lipidomic analysis was performed to decipher the lipids involved in the observed transformations. As general results, aldrin exposure showed a global decrease in phospholipids and sphingolipids, and aroclor and CPF showed an increase of certain phospholipids, glycosphingolipids as well as a remarkable increase of some cardiolipin species. Furthermore, the three exposures resulted in an increase of some triglyceride species. In conclusion, some significant changes in lipids were identified and thus we postulate that some lipid compounds and lipid metabolic pathways could be involved in the acquisition of the malignant phenotype in exposed prostate cancer cells to the selected EDs. - Highlights: • Aldrin, aroclor and chlorpyrifos induced an aggressive phenotype in DU145 cells. • An untargeted lipidomic analysis has been performed on chronic exposed cells. • Lipidomic results showed changes in specific lipid species under chronic exposure. • These lipids may have a role in the

  4. Phenotypic malignant changes and untargeted lipidomic analysis of long-term exposed prostate cancer cells to endocrine disruptors

    International Nuclear Information System (INIS)

    Endocrine disruptors (EDs) are a class of environmental toxic molecules able to interfere with the normal hormone metabolism. Numerous studies involve EDs exposure to initiation and development of cancers, including prostate cancer. In this work, three different EDs (aldrin, aroclor 1254 and chlorpyrifos (CPF)) were investigated as potential inducers of a malignant phenotype in DU145 prostate cancer cells after a chronic exposure. Epithelial to mesenchymal transition (EMT) induction, proliferation, migration, colony formation and release of metalloproteinase 2 (MMP-2) were analyzed in 50-day exposed cells to the selected EDs. As a result, aldrin and CPF exposure led to an EMT induction (loss of 16% and 14% of E-cadherin levels, respectively, compared to the unexposed cells). Aroclor and CPF presented an increased migration (134% and 126%, respectively), colony formation (204% and 144%, respectively) and MMP-2 release (137% in both cases) compared to the unexposed cells. An untargeted lipidomic analysis was performed to decipher the lipids involved in the observed transformations. As general results, aldrin exposure showed a global decrease in phospholipids and sphingolipids, and aroclor and CPF showed an increase of certain phospholipids, glycosphingolipids as well as a remarkable increase of some cardiolipin species. Furthermore, the three exposures resulted in an increase of some triglyceride species. In conclusion, some significant changes in lipids were identified and thus we postulate that some lipid compounds and lipid metabolic pathways could be involved in the acquisition of the malignant phenotype in exposed prostate cancer cells to the selected EDs. - Highlights: • Aldrin, aroclor and chlorpyrifos induced an aggressive phenotype in DU145 cells. • An untargeted lipidomic analysis has been performed on chronic exposed cells. • Lipidomic results showed changes in specific lipid species under chronic exposure. • These lipids may have a role in the

  5. Changes of cell factor in bronchoalveolar lavage fluid in rats exposed to silica

    Institute of Scientific and Technical Information of China (English)

    张玮

    2014-01-01

    Objective To investigate the changes in the levels of inflammatory cytokines in bronchoalveolar lavage fluid(BALF)in rats exposed to silica dust.Methods Experimental rats were randomly divided into control group and three experimental groups(doses of dust:15,30,and 60mg/ml),with 42 rats in each group.Each rat in the control group was treated with 1 ml of normal saline by intratracheal instillation,while each rat in the experimental groups was exposed to 1

  6. Strong HIV-1-Specific T Cell Responses in HIV-1-Exposed Uninfected Infants and Neonates Revealed after Regulatory T Cell Removal

    OpenAIRE

    Legrand, Fatema A.; Nixon, Douglas F.; Loo, Christopher P.; Erika Ono; Chapman, Joan M; Maristela Miyamoto; Diaz, Ricardo S.; Amélia M N Santos; Succi, Regina C. M.; Jacob Abadi; Rosenberg, Michael G.; Maria Isabel de Moraes-Pinto; Esper G Kallas

    2006-01-01

    BACKGROUND: In utero transmission of HIV-1 occurs on average in only 3%-15% of HIV-1-exposed neonates born to mothers not on antiretroviral drug therapy. Thus, despite potential exposure, the majority of infants remain uninfected. Weak HIV-1-specific T-cell responses have been detected in children exposed to HIV-1, and potentially contribute to protection against infection. We, and others, have recently shown that the removal of CD4(+) CD25(+) T-regulatory (Treg) cells can reveal strong HIV-1...

  7. Evaluation of cytotoxicity, morphological alterations and oxidative stress in Chinook salmon cells exposed to copper oxide nanoparticles.

    Science.gov (United States)

    Srikanth, Koigoora; Pereira, Eduarda; Duarte, Armando C; Rao, Janapala Venkateswara

    2016-05-01

    The current study is aimed to study cytotoxicity and oxidative stress mediated changes induced by copper oxide nanoparticles (CuO NPs) in Chinook salmon cells (CHSE-214). To this end, a number of biochemical responses are evaluated in CHSE-214 cells which are as follows [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] MTT, neutral red uptake (NRU), lactate dehydrogenase (LDH), protein carbonyl (PC), lipid peroxidation (LPO), oxidised glutathione (GSSG), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione sulfo-transferase (GST), superoxide dismutase (SOD), catalase (CAT), 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and reactive oxygen species (ROS), respectively. The 50 % inhibition concentration (IC50) of CuO NPs to CHSE-214 cells after 24 h exposure was found to be 19.026 μg ml(-1). Viability of cells was reduced by CuO NPs, and the decrease was dose dependent as revealed by the MTT and NRU assay. CHSE-214 cells exposed to CuO NPs induced morphological changes. Initially, cells started to detach from the surface (12 h), followed by polyhedric, fusiform appearance (19 h) and finally the cells started to shrink. Later, the cells started losing their cellular contents leading to their death only after 24 h. LDH, PC, LPO, GSH, GPx, GST, SOD, CAT, 8-OHdG and ROS responses were seen significantly increased with the increase in the concentration of CuO NPs when compared to their respective controls. However, significant decrease in GSSG was perceptible in CHSE-214 cells exposed to CuO NPs in a dose-dependent manner. Our data demonstrated that CuO NPs induced cytotoxicity in CHSE-214 cells through the mediation of oxidative stress. The current study provides a baseline for the CuO NPs-mediated cytotoxic assessment in CHSE-214 cells for the future studies. PMID:26115719

  8. Cell viability, reactive oxygen species, apoptosis, and necrosis in myoblast cultures exposed to low-level infrared laser.

    Science.gov (United States)

    Alexsandra da Silva Neto Trajano, Larissa; da Silva, Camila Luna; de Carvalho, Simone Nunes; Cortez, Erika; Mencalha, André Luiz; de Souza da Fonseca, Adenilson; Stumbo, Ana Carolina

    2016-07-01

    Low-level infrared laser is considered safe and effective for treatment of muscle injuries. However, the mechanism involved on beneficial effects of laser therapy are not understood. The aim was to evaluate cell viability, reactive oxygen species, apoptosis, and necrosis in myoblast cultures exposed to low-level infrared laser at therapeutic fluences. C2C12 myoblast cultures at different (2 and 10 %) fetal bovine serum (FBS) concentrations were exposed to low-level infrared laser (808 nm, 100 mW) at different fluences (10, 35, and 70 J/cm(2)) and evaluated after 24, 48, and 72 h. Cell viability was evaluated by WST-1 assay; reactive oxygen species (ROS), apoptosis, and necrosis were evaluated by flow cytometry. Cell viability was decreased atthe lowest FBS concentration. Laser exposure increased the cell viability in myoblast cultures at 2 % FBS after 48 and 72 h, but no significant increase in ROS was observed. Apoptosis was decreased at the higher fluence and necrosis was increased at lower fluence in myoblast cultures after 24 h of laser exposure at 2 % FBS. No laser-induced alterations were obtained at 10 % FBS. Results show that level of reactive oxygen species is not altered, at least to those evaluated in this study, but low-level infrared laser exposure affects cell viability, apoptosis, and necrosis in myoblast cultures depending on laser fluence and physiologic conditions of cells. PMID:26886589

  9. Mutagenic adaptive response to high-LET radiation in human lymphoblastoid cells exposed to X-rays

    International Nuclear Information System (INIS)

    The ability of cells to adapt low-dose or low-dose rate radiation is well known. High-LET radiation has unique characteristics, and the data concerning low doses effects and high-LET radiation remain fragmented. In this study, we assessed in vitro the ability of low doses of X-rays to induce an adaptive response (AR) to a subsequent challenging dose of heavy-ion radiation. Lymphoblastoid cells (TK6, AHH-1, NH32) were exposed to priming 0.02-0.1 Gy X-rays, followed 6 h later by challenging 1 Gy heavy-ion radiation (carbon-ion: 20 and 40 keV/μm, neon-ion: 150 keV/μm). Pre-exposure of p53-competent cells resulted in decreased mutation frequencies at hypoxanthine-guanine phosphoribosyl transferase locus and different H2AX phosphorylation kinetics, as compared to cells exposed to challenging radiation alone. This phenomenon did not seem to be linked with cell cycle effects or radiation-induced apoptosis. Taken together, our results suggested the existence of an AR to mutagenic effects of heavy-ion radiation in lymphoblastoid cells and the involvement of double-strand break repair mechanisms.

  10. Alteration of Peripheral Blood T-Reg Cells and Cytokines Production in Angiography Personnel Exposed to Scattered X-Rays

    Directory of Open Access Journals (Sweden)

    Ebrahim Torkabadi

    2007-12-01

    Full Text Available Angiocardiography is an X-ray examination of the blood vessels or chambers of the heart. Cardiologists and staff members applying this procedure are exposed to high levels of scattered radiation. In our previous study the incidence of unstable chromosomal aberrations and cytokinesis-blocked micronuclei were found to be significantly higher in exposed individuals than the age and sex matched controls. In the present study we assessed cytokine production by peripheral blood mononuclear cells of the above cases and the percentage of Treg cells. According to film dosimeter analysis, personnels received 0.25-15 mSv during the previous year (average of 3 mSv/y. Isolated PBMCs from the test and control groups were stimulated with Phorbol Myristate Acetate/ Ionomycin (PMA/I. Cytokine production was measured in the supernatants of cultured lymphocytes. The percentage of Treg cells was studied by flow cytometry. The production of IL-10 and IL-5 was significantly down-regulated in the test group compared to the control group. In contrast, IL-12 was up-regulated. Yet, no statistically significant difference was found for IFN- γ between two groups. In addition, we found higher percentage of CD4+CD25+bright Treg cells in the study group compared to the controls. Taken together, it was shown that low doses of scattered X-rays could skew cytokine profile of peripheral blood mononuclear cells in favour of inflammatory response causing the increase of Treg cells.

  11. Influence of normal epithelial cells on the development and expression of the neoplastic phenotype in carcinogen exposed rat tracheal epithelial cells

    International Nuclear Information System (INIS)

    An inhibitory effect of normal epithelial cells on both preneoplastic and neoplastic tracheal epithelial cells using a cell culture as well as an in vivo model has been demonstrated. It is not clear at present whether inhibition observed in vivo in reconstructed tracheal mucosa occurs via the same mechanism as that occurring in intact carcinogen-exposed tracheal transplants, or whether the inhibition observed in cell culture shares any common mechanism with inhibition observed in cell co-cultures or in conditioned medium experiments. They are currently carrying out experiments designed to examine and elucidate these unresolved questions

  12. N-Hydroxycinnamide derivatives of osthole presenting genotoxicity and cytotoxicity against human colon adenocarcinoma cells in vitro and in vivo.

    Science.gov (United States)

    Liu, Ling-Yu; Huang, Wei-Jan; Lin, Ren-Jye; Lin, Shyr-Yi; Liang, Yu-Chih

    2013-11-18

    Osthole is extracted from the Chinese herbs Cnidium monnieri and Angelica pubescens, and it was found to have antitumor activity in vitro and in vivo. A series of osthole derivatives have been synthesized, and the N-hydroxycinnamide derivatives of osthole, WJ1376-1 and WJ1398-1 were found to have the greatest potential against human colon adenocarcinoma cells. In contrast to the parental osthole, both WJ1376-1 and WJ1398-1 were found to induce multinucleation and polyploidy by microscopic observation and flow cytometry. WJ1376-1 and WJ1398-1 significantly activated ataxia telangiectasia and rad3 related (ATR) kinase, which triggered activation of the checkpoint kinase 2 (Chk2) signaling pathway and then down regulated Cdc25 phosphatase and Cdc2/cyclin B kinase activities. WJ1376-1 and WJ1398-1 also inhibited the phosphorylation of Aurora A kinase, which is associated with important processes during mitosis. The presence of a "comet" DNA fragment and phosphorylation of p53 at Ser 15 clearly indicated that DNA damage occurred with WJ1376-1 and WJ1398-1 treatment. WJ1376-1 and WJ1398-1 ultimately induced apoptosis as evidenced by the upregulation of Bad and activation of caspases-3, -7, and -9. Furthermore, WJ1376-1 and WJ1398-1 also showed a great effect in attenuating tumor growth without affecting the body weight of xenograft nude mice. Taken together, these results suggest that the toxic activities of WJ1376-1 and WJ1398-1 were dissimilar to that of the parental osthole, which can induce cell polyploidy and G2/M cell cycle arrest in colon adenocarcinoma cells and may provide a potential therapeutic target for colon cancer treatment in the future. PMID:24127835

  13. The opportunistic pathogen Pseudomonas aeruginosa activates the DNA double-strand break signaling and repair pathway in infected cells

    International Nuclear Information System (INIS)

    Highly hazardous DNA double-strand breaks can be induced in eukaryotic cells by a number of agents including pathogenic bacterial strains. We have investigated the genotoxic potential of Pseudomonas aeruginosa, an opportunistic pathogen causing devastating nosocomial infections in cystic fibrosis or immunocompromised patients. Our data revealed that infection of immune or epithelial cells by P. aeruginosa triggered DNA strand breaks and phosphorylation of histone H2AX (γH2AX), a marker of DNA double-strand breaks. Moreover, it induced formation of discrete nuclear repair foci similar to gamma-irradiation-induced foci, and containing γH2AX and 53BP1, an adaptor protein mediating the DNA-damage response pathway. Gene deletion, mutagenesis, and complementation in P. aeruginosa identified ExoS bacterial toxin as the major factor involved in γH2AX induction. Chemical inhibition of several kinases known to phosphorylate H2AX demonstrated that Ataxia Telangiectasia Mutated (ATM) was the principal kinase in P. aeruginosa-induced H2AX phosphorylation. Finally, infection led to ATM kinase activation by an auto-phosphorylation mechanism. Together, these data show for the first time that infection by P. aeruginosa activates the DNA double-strand break repair machinery of the host cells. This novel information sheds new light on the consequences of P. aeruginosa infection in mammalian cells. As pathogenic Escherichia coli or carcinogenic Helicobacter pylori can alter genome integrity through DNA double-strand breaks, leading to chromosomal instability and eventually cancer, our findings highlight possible new routes for further investigations of P. aeruginosa in cancer biology and they identify ATM as a potential target molecule for drug design. (authors)

  14. Proliferation and survival of L5178Y murine lymphoma cells exposed to tritiated water and tritiated thymidine

    International Nuclear Information System (INIS)

    Two strains of murine lymphoma cells L5178Y, inversely cross-sensitive to X-rays and UV light, were exposed to various concentrations of tritiated water and tritiated thymidine. The exposure was carried out at 370C to simulate conditions of in vivo chronic exposure. Tritiated water was used at 2, 4 and 100 μCi/ml (74 and 148 kBq/ml and 3.7 MBq/ml) and tritiated thymidine at 0.05 μCi/ml (1.85 kBq/ml). The exposure was carried out for 4, 25, 50, 100, 200 and 400 h. The strains exposed, L5178Y-R and L5178Y-S, which differ in sensitivity to acute irradiation, also differ in susceptibility to tritiated compounds. It was found that the development of the exposed cell populations proceeds according to a reproducible pattern: growth phases can be distinguished that differ both in their rate of proliferation and in their cell reproductive capacity determined after transfer into a non-radioactive medium. (author)

  15. Effectiveness of compensation of lymphoid defficiency in lethally exposed animals through transplantation of cryopreserved lymphoid cells

    International Nuclear Information System (INIS)

    In experiments on lethally exposed (LDsub(100/15)) (CBAxC57B1)F1 mice treated with bone marrow, it was demonstrated that transplantation of syngeneic cryopreserved lymphocytes accelerates markedly the recovery of cellularity of bone marrow, spleen and thymus and rises the level of humoral and cellular immune response of the organism

  16. Detection of Sperm DNA Damage in Workers Exposed to Benzene by Modified Single Cell Gel Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Bo SONG; Zhi-ming CAI; Xin LI; Li-xia DENG; Qiao ZHANG; Lu-kang ZHENG

    2005-01-01

    Objective To assess the effect of benzene on sperm DNA damageMethods Twenty-seven benzene-exposed workers were selected as exposed groupand 35 normal sperm donors as control group. Air concentration of benzene series inworkshop was determined by gas chromatography. As an internal exposure dose ofbenzene, the concentration of trans, trans-muconic acid (ttMA) was determined byhigh performance liquid chromatography. DNA was detected by modified single cellgel electrophoresis (SCGE).Results The air concentrations of benzene, toluene and xylene at the workplace were86.49 ± 2.83 mg/m3, 97.20 ±3.52 mg/m3 and 97.45 ±2.10 mg/m3, respectively.Urinary ttMA in exposed group (1.040 ± 0.617 mg/L) was significantly higher thanthat of control group (0.819 ± 0.157 mg/L). The percentage of head DNA, determinedby modified SCGE method, significantly decreased in the exposed group (n=13, 70.18%± 7.36%) compared with the control (n=16, 90.62% ± 2.94%)(P<0.001).Conclusion The modified SCGE method can be used to investigate the damage ofsperm DNA. As genotoxin and reprotoxins, benzene had direct effect on the germ cellsduring the spermatogenesiss.

  17. CtIP-dependent DNA resection is required for DNA damage checkpoint maintenance but not initiation

    DEFF Research Database (Denmark)

    Kousholt, Arne Nedergaard; Fugger, Kasper; Hoffmann, Saskia;

    2012-01-01

    To prevent accumulation of mutations, cells respond to DNA lesions by blocking cell cycle progression and initiating DNA repair. Homology-directed repair of DNA breaks requires CtIP-dependent resection of the DNA ends, which is thought to play a key role in activation of ATR (ataxia telangiectasia...

  18. Evaluation of DNA damage in agricultural workers exposed to pesticides using single cell gel electrophoresis (comet assay

    Directory of Open Access Journals (Sweden)

    Raminderjeet Kaur

    2011-01-01

    Full Text Available Background : Pesticides are used in agriculture to protect crops, but they pose a potential risk to farmers and environment. The aim of the present study is to investigate the relation between the occupational exposure to various pesticides and the presence of DNA damage. Materials and Methods : Blood samples of 210 exposed workers (after a day of intense spraying and 50 control subjects belonging to various districts of Punjab (India were evaluated using Comet assay. Sixty workers who showed DNA damage were selected for follow up at 5-6 months after the first sampling during a low or null spraying period. Results : Significant differences were found in DNA damage between freshly exposed workers and controls and freshly exposed and followed up cases. There was significant increase in the comet parameters viz. mean comet tail length and frequency of cells showing migration in exposed workers as compared to controls (72.22 ± 20.76 vs. 46.92 ± 8.17, P<0.001; 31.79 vs. 5.77, P<0.001. In the second samples, followed up cases showed significant decrease in frequency of damaged cells as compared to freshly exposed workers of first sampling (P<0.05. The confounding factors such as variable duration of pesticide exposure, age, smoking, drinking and dietary habits etc which were expected to modulate the damage, were instead found to have no significant effect on DNA fragmentation. Conclusion : The evidence of a genetic hazard related to exposure resulting from the intensive use of pesticides stresses the need for educational programs for agricultural workers to reduce the use of chemicals in agriculture.

  19. Antioxidant Activity of Ixora parviflora in a Cell/Cell-Free System and in UV-Exposed Human Fibroblasts

    Directory of Open Access Journals (Sweden)

    Hsiu-Mei Chiang

    2011-07-01

    Full Text Available Polyphenols and flavonoids possess a variety of biological activities including antioxidant and anti-tumor activities. Ixora parviflora is a member of the flavonoid-rich Rubiaceae family of flowering plants and used as folk medicine in India. The aim of this study was to investigate the antioxidant activity of Ixora parviflora extract (IPE in a cell-free system and erythrocytes, and the ability of IPE to inhibit reactive oxygen species (ROS generation in human fibroblasts (Hs68 after ultraviolet (UV exposure. Various in vitro antioxidant assays were employed in this study. The extraction yield of IPE was 17.4 ± 3.9%, the total phenolic content of IPE was 26.2 μg gallic acid equivalent (GAE/mg leaves dry weight and the total flavonoids content was 54.2 ± 4.4 μg quercetin equvalent (QE/mg extract. The content of chlorogenic acid was 9.7 ± 1.2 mg/g extract. IPE at 1000 μg/mL exhibited a reducing capacity of 90.5 ± 0.6%, a 1,1-diphenyl-2-picrylhydrazy (DPPH radical scavenging activity of 96.0 ± 0.4%, a ferrous chelating activity of 72.2 ± 3.5%, a hydroxyl radical scavenging activity of 96.8 ± 1.4%, and a hydrogen peroxide scavenging activity of 99.5 ± 3.3%. IPE at 500 μg/mL also possessed inhibitory activity against 2,2'-azobis (2-methylpropionamidine dihydrochloride (AAPH-induced hemolysis of erythrocytes (89.4 ± 1.8% and resulted in a 52.9% reduction in ROS generation in UV-exposed fibroblasts. According to our findings, IPE is a potent antioxidant and a potential anti-photoaging agent.

  20. B cells exposed to enterobacterial components suppress development of experimental colitis

    DEFF Research Database (Denmark)

    Schmidt, Esben Gjerløff Wedebye; Larsen, Hjalte List; Kristensen, Nanna Ny; Poulsen, Steen Seier; Claesson, Mogens Helweg; Pedersen, Anders Elm

    2012-01-01

    development of colitis. Suppression was dependent on B cell-derived IL-10, as co-transfer of IL-10 knockout ebx-B cells failed to suppress colitis. Ebx-B cell-mediated suppression of colitis was associated with a decrease in interferon gamma (IFN-¿)-producing T(H) 1 cells and increased frequencies of Foxp3...

  1. rIL-10 enhances IL-10 signalling proteins in foetal alveolar type II cells exposed to hyperoxia.

    Science.gov (United States)

    Lee, Hyeon-Soo; Lee, Dong Gun

    2015-07-01

    Although the mechanisms by which hyperoxia promotes bronchopulmonary dysplasia are not fully defined, the inability to maintain optimal interleukin (IL)-10 levels in response to injury secondary to hyperoxia seems to play an important role. We previously defined that hyperoxia decreased IL-10 production and pre-treatment with recombinant IL-10 (rIL-10) protected these cells from injury. The objectives of these studies were to investigate the responses of IL-10 receptors (IL-10Rs) and IL-10 signalling proteins (IL-10SPs) in hyperoxic foetal alveolar type II cells (FATIICs) with and without rIL-10. FATIICs were isolated on embryonic day 19 and exposed to 65%-oxygen for 24 hrs. Cells in room air were used as controls. IL-10Rs protein and mRNA were analysed by ELISA and qRT-PCR, respectively. IL-10SPs were assessed by Western blot using phospho-specific antibodies. IL-10Rs protein and mRNA increased significantly in FATIICs during hyperoxia, but JAK1 and TYK2 phosphorylation showed the opposite pattern. To evaluate the impact of IL-8 (shown previously to be increased) and the role of IL-10Rs, IL-10SPs were reanalysed in IL-8-added normoxic cells and in the IL-10Rs' siRNA-treated hyperoxic cells. The IL-10Rs' siRNA-treated hyperoxic cells and IL-8-added normoxic cells showed the same pattern in IL10SPs with the hyproxic cells. And pre-treatment with rIL-10 prior to hyperoxia exposure increased phosphorylated IL-10SPs, compared to the rIL-10-untreated hyperoxic cells. These studies suggest that JAK1 and TYK2 were significantly suppressed during hyperoxia, where IL-8 may play a role, and rIL-10 may have an effect on reverting the suppressed JAK1 and TYK2 in FATIICs exposed to hyperoxia. PMID:26059905

  2. Increased frequency of spontaneous neoplastic transformation in progeny of bystander cells from cultures exposed to densely ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

    Full Text Available An increased risk of carcinogenesis caused by exposure to space radiation during prolonged space travel is a limiting factor for human space exploration. Typically, astronauts are exposed to low fluences of ionizing particles that target only a few cells in a tissue at any one time. The propagation of stressful effects from irradiated to neighboring bystander cells and their transmission to progeny cells would be of importance in estimates of the health risks of exposure to space radiation. With relevance to the risk of carcinogenesis, we investigated, in model C3H 10T½ mouse embryo fibroblasts (MEFs, modulation of the spontaneous frequency of neoplastic transformation in the progeny of bystander MEFs that had been in co-culture 10 population doublings earlier with MEFs exposed to moderate doses of densely ionizing iron ions (1 GeV/nucleon or sparsely ionizing protons (1 GeV. An increase (P<0.05 in neoplastic transformation frequency, likely mediated by intercellular communication through gap junctions, was observed in the progeny of bystander cells that had been in co-culture with cells irradiated with iron ions, but not with protons.

  3. Workshop on The Epidemiology of the ATM Gene: Impact on Breast Cancer Risk and Treatment, Present Status and Future Focus, Lillehammer, Norway, 29 June 2002

    International Nuclear Information System (INIS)

    The role of ataxia-telangiectasia mutated (ATM) heterozygosity in cancer is uncertain. In vitro studies of cells from ATM heterozygotes provide strong evidence of radiation sensitivity. Some, but not all, clinical studies suggest an increased risk of breast cancer among ATM gene carriers, and this risk may be greater among those exposed to radiation. This possible excess risk of breast cancer associated with ATM heterozygosity constitutes the basis for several genetic epidemiological studies designed to clarify the role that the ATM gene plays in the etiology of breast and other cancers. The primary focus of this international, multidisciplinary, National Cancer Institute-sponsored workshop was to discuss ongoing and planned epidemiologic studies aimed at understanding the complexities of the ATM gene and its role in carcinogenesis. The invited participants were from diverse disciplines including molecular and clinical genetics, radiation biology and physics, epidemiology, biostatistics, pathology, and medicine. In the present meeting report, the aims of each project are described

  4. Zerumbone increases oxidative stress in a thiol-dependent ROS-independent manner to increase DNA damage and sensitize colorectal cancer cells to radiation

    International Nuclear Information System (INIS)

    Locally advanced rectal cancers are treated with neoadjuvant chemoradiation therapy followed by surgery. In a minority (∽20%) of patients, no tumor is present at the time of surgery; these patients with a complete pathologic response (pathCR) to neoadjuvant therapy have better treatment outcomes. Unfortunately, the inherent radioresistance of colorectal cancer (CRC) cells dictates that the majority of patients do not achieve a pathCR. Efforts to improve these odds have fueled the search for novel, relatively less-toxic radiosensitizers with distinct molecular mechanism(s) and broad-spectrum anticancer activities. Here, we use zerumbone, a sesquiterpene from the edible ginger (Zingiber zerumbet Smith), to enhance radiosensitivity of CRC cells. Short exposure to zerumbone (7 h) profoundly sensitized CRC cells, independent of their p53 or k-RAS status. Zerumbone enhanced radiation-induced cell cycle arrest (G2/M), increased radiation-induced apoptosis, but induced little apoptosis by itself. Zerumbone significantly enhanced radiation-induced DNA damage, as evident by delayed resolution of post-irradiation nuclear γH2AX foci, whereas zerumbone treatment alone did not induce γH2AX foci formation. Zerumbone pretreatment inhibited radiation-induced nuclear expression of DNA repair proteins ataxia-telangiectasia mutated (ATM) and DNA-PKcs. Interestingly, zerumbone-mediated radiosensitization did not involve reactive oxygen species (ROS), but was mediated through depletion of cellular glutathione (GSH). Ability of only thiol-based antioxidants to abrogate zerumbone-mediated radiosensitization further corroborated this hypothesis. The α,β-unsaturated carbonyl group in zerumbone was found to be essential for its bioactivity as zerumbone analog α-Humulene that lacks this functional group, could neither radiosensitize CRC cells, nor deplete cellular GSH. Our studies elucidate novel mechanism(s) of zerumbone's ability to enhance CRC radiosensitivity

  5. Assessment of micronucleus frequency in exfoliated buccal epithelial cells among fisher folks exposed to mine tailings in Marinduque Island, Philippines

    Institute of Scientific and Technical Information of China (English)

    Elena M Ragragio; Celeste P Belleza; Mark C Narciso; Glenn L Sia Su

    2010-01-01

    Objective:To evaluate the potential toxic effects of mine tailings exposure among the fisher folks residing near and far from the Calancan Bay, Marinduque, using the micronucleus assay as an endpoint.Methods: The fisher folks residing near and far from the Calancan Bay were interviewed and the presence and frequency of cells with micronucleus in exfoliated buccal epithelial cells were examined.Results: Results showed that the prevalence of cells with micronucleus was higher among the fisher folks who were directly exposed to the mine tailings as compared with those fisher folks who reside in a community without exposure of mine tailings and history of mining (P<0.05).Conclusions: The presence and the significant difference in the cells with micronuclei observed near the Calancan Bay could possibly indicate a prolonged chemical stress caused by the toxic heavy metals in the mine tailings and the environment.

  6. Lung Surfactant Gelation Induced by Epithelial Cells Exposed to Air Pollution or Oxidative Stress

    OpenAIRE

    Anseth, Jay W.; Goffin, An J.; Fuller, Gerald G.; Ghio, Andrew J; Kao, Peter N.; Upadhyay, Daya

    2005-01-01

    Lung surfactant lowers surface tension and adjusts interfacial rheology to facilitate breathing. A novel instrument, the interfacial stress rheometer (ISR), uses an oscillating magnetic needle to measure the shear viscosity and elasticity of a surfactant monolayer at the air–water interface. The ISR reveals that calf lung surfactant, Infasurf, exhibits remarkable fluidity, even when exposed to air pollution residual oil fly ash (ROFA), hydrogen peroxide (H2O2), or conditioned media from resti...

  7. DNA damage in gill cells of Corbicula japonica exposed to natural and anthropogenic stressors

    OpenAIRE

    Valentina Vladimirovna Slobodskova

    2015-01-01

    Bivalve mollusks are sensitive biomarkers of aquatic ecosystem pollution. The impact of human activities on the environmental is an ongoing and increasing problem. There are many potentially dangerous chemicals that dissolve in water. Aquatic organisms are exposed to these chemicals, which can lead to morphological alterations and change certain physiological processes in their organs. The monitoring of changes in various biochemical parameters at the individual species level of organisms may...

  8. Immunostimulatory Activity of the Cytokine-Based Biologic, IRX-2, on Human Papillomavirus-Exposed Langerhans Cells.

    Science.gov (United States)

    Da Silva, Diane M; Woodham, Andrew W; Naylor, Paul H; Egan, James E; Berinstein, Neil L; Kast, W Martin

    2016-05-01

    Langerhans cells (LCs) are the antigen-presenting cells of the epithelial layer and are responsible for initiating immune responses against skin and mucosa-invading viruses. Human papillomavirus (HPV)-mediated suppression of LC function is a crucial mechanism of HPV immune evasion, which can lead to persistent infection and development of several human cancers, including cervical, anal, and head and neck cancers. The cell-derived cytokine-based biologic, IRX-2, consists of multiple well-defined cytokines and is broadly active on various immune cell subsets. In this study, we investigated primary human LC activation after exposure to HPV16, followed by treatment with IRX-2 in vitro, and evaluated their subsequent ability to induce HPV16-specific T cells. In contrast to its activity on dendritic cells, HPV16 alone is not sufficient to induce phenotypic and functional activation of LCs. However, IRX-2 induces a significant upregulation of antigen presentation and costimulatory molecules, T helper 1 (Th1)-associated cytokine release, and chemokine-directed migration of LCs pre-exposed to HPV16. Furthermore, LCs treated with IRX-2 after HPV16 exposure induced CD8(+) T-cell responses against specific HLA-A*0201-binding HPV16 T-cell epitopes. The present study suggests that IRX-2 is an attractive immunomodulator for assisting the immune response in eradication of HPV-infected cells, thereby potentially preventing HPV-induced cancers. PMID:26653678

  9. Mast cells in the intestine and gills of the sea bream, Sparus aurata, exposed to a polychlorinated biphenyl, PCB 126.

    Science.gov (United States)

    Lauriano, Eugenia Rita; Calò, Margherita; Silvestri, Giuseppa; Zaccone, Daniele; Pergolizzi, Simona; Lo Cascio, Patrizia

    2012-02-01

    The presence of mast cells has been reported in all classes of vertebrates, including many teleost fish families. The mast cells of teleosts, both morphologically and functionally, show a close similarity to the mast cells of mammals. Mast cells of teleosts, localized in the vicinity of blood vessels of the intestine, gills and skin, may play an important role in the mechanisms of inflammatory response, because they express a number of functional proteins, including piscidins, which are antimicrobical peptides that act against a broad-spectrum of pathogens. An increase in the number of mast cells in various tissues and organs of teleosts seems to be linked to a wide range of stressful conditions, such as exposure to heavy metals (cadmium, copper, lead and mercury), exposure to herbicides and parasitic infections. This study analyzed the morphological localization and abundance of mast cells in the intestine and gills of sea bream, Sparus aurata, after a 12, 24 or 72 h exposure to PCB 126, a polychlorinated biphenyl, which is a potent immunotoxic agent. In the organs of fish exposed to PCB 126, it was observed that in addition to congestion of blood vessels, there was extravasation of red blood cells, infiltration of lymphocytes, and a progressive increase in numbers of mast cells. These data confirm the immunotoxic action of PCB, and the involvement of mast cells in the inflammatory response. PMID:21565388

  10. Construction and identification of subtracted cDNA library in bone marrow cells of radon-exposed mice

    International Nuclear Information System (INIS)

    Objective: To construct and identify subtracted cDNA library in bone marrow cells of mice exposed to radon inhalation. Methods: Adult male BALB/c mice, weighing 18-22 g, were placed in a multi- functional radon chamber. One group of mice was exposed to radon up to the accumulative dose of 105 work level month (WLM). The control group of mice was housed in a room with an accumulative dose of 1 WLM. To construct a subtracted cDNA library enriched with differentially expressed genes, the SMART technique and the suppression subtractive hybridization were performed. The obtained forward and reverse cDNA fragments were directly inserted into pMD18-T vector and transformed into E. coli JM109. The inserting cDNA fragments were screened by the blue-and-white blot screening and nested PCR of bacterium liquid. Results: The 244 of 285 white bacteria clones obtained randomly were positive clones contained 100-1100 bp inserted cDNA fragments. Conclusions: The forward and reverse subtracted cDNA library in bone marrow cells of mice exposed to radon inhalation is successfully constructed. (authors)

  11. Low-level laser therapy: Effects on human face aged skin and cell viability of HeLa cells exposed to UV radiation

    OpenAIRE

    Mezghani Sana; Hammami Amira; Amri Mohamed

    2015-01-01

    Chronic and excessive exposure to UV radiation leads to photoaging and photocarcinogenesis. Adequate protection of the skin against the deleterious effects of UV irradiation is essential. Low-level laser therapy (LLLT) is a light source in the red to near-infrared range that has been accepted in a variety of medical applications. In this study, we explored the effect of LLLT in human face aged skin and the cell viability of HeLa cells exposed to UV radiatio...

  12. Phosphorylated histone H2AX in relation to cell survival in tumor cells and xenografts exposed to single and fractionated doses of X-rays

    International Nuclear Information System (INIS)

    Background and purpose: Human tumor cell lines grown as monolayers or xenograft tumors were exposed to single or multiple fractions of X-rays and the ability to use residual γH2AX to identify radiosensitive cells was assessed. Materials and methods: Twenty-four hour after exposure to single or daily fractions of X-rays, human tumor cells from monolayers or xenografts were analyzed for clonogenic surviving fraction. Cells were also fixed and labeled with anti-γH2AX antibodies for analysis by flow and image cytometry. The relative amount of residual γH2AX and the percentage of cells with <3 foci were compared with the clonogenic surviving fraction measured for the same population. Results: The fraction of γH2AX remaining 24 h after X-irradiation relative to peak levels 1 h after exposure was correlated with radiosensitivity (SF2) for 18 human tumor cell lines. The fraction of SiHa, C33A and WiDr cells with <3 γH2AX foci was predictive of clonogenic surviving fraction for both monolayer cells exposed to either single doses or up to 5 fractions. Similar results were obtained using cells from xenograft tumors of irradiated mice. Conclusion: The percentage of tumor cells that retain γH2AX foci 24 h after single or fractionated doses appears to be a useful measure of cellular radiosensitivity that is potentially applicable in the clinic

  13. Lucifer Yellow uptake by CHO cells exposed to magnetic and electric pulses

    OpenAIRE

    Miklavčič, Damijan; Towhidi, Leila; Firoozabadi, S. M. P.; Mozdarani, Hossein

    2012-01-01

    Background The cell membrane acts as a barrier that hinders free entrance of most hydrophilic molecules into the cell. Due to numerous applications in medicine, biology and biotechnology, the introduction of impermeant molecules into biological cells has drawn considerable attention in the past years. One of the most famous methods in this field is electroporation, in which electric pulses with high intensity and short duration are applied to the cells. The aim of our study was to investigate...

  14. Associations of ATM Polymorphisms With Survival in Advanced Esophageal Squamous Cell Carcinoma Patients Receiving Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To investigate whether single nucleotide polymorphisms (SNPs) in the ataxia telangiectasia mutated (ATM) gene are associated with survival in patients with esophageal squamous cell carcinoma (ESCC) receiving radiation therapy or chemoradiation therapy or surgery only. Methods and Materials: Four tagSNPs of ATM were genotyped in 412 individuals with clinical stage III or IV ESCC receiving radiation therapy or chemoradiation therapy, and in 388 individuals with stage I, II, or III ESCC treated with surgery only. Overall survival time of ESCC among different genotypes was estimated by Kaplan-Meier plot, and the significance was examined by log-rank test. The hazard ratios (HRs) and 95% confidence intervals (CIs) for death from ESCC among different genotypes were computed by a Cox proportional regression model. Results: We found 2 SNPs, rs664143 and rs664677, associated with survival time of ESCC patients receiving radiation therapy. Individuals with the rs664143A allele had poorer median survival time compared with the rs664143G allele (14.0 vs 20.0 months), with the HR for death being 1.45 (95% CI 1.12-1.89). Individuals with the rs664677C allele also had worse median survival time than those with the rs664677T allele (14.0 vs 23.5 months), with the HR of 1.57 (95% CI 1.18-2.08). Stratified analysis showed that these associations were present in both stage III and IV cancer and different radiation therapy techniques. Significant associations were also found between the SNPs and locosregional progression or progression-free survival. No association between these SNPs and survival time was detected in ESCC patients treated with surgery only. Conclusion: These results suggest that the ATM polymorphisms might serve as independent biomarkers for predicting prognosis in ESCC patients receiving radiation therapy

  15. Associations of ATM Polymorphisms With Survival in Advanced Esophageal Squamous Cell Carcinoma Patients Receiving Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Du, Zhongli [State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Department of Etiology and Carcinogenesis (Beijing Key Laboratory for Carcinogenesis and Cancer Prevention), Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Zhang, Wencheng [Department of Radiation Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Zhou, Yuling; Yu, Dianke; Chen, Xiabin; Chang, Jiang; Qiao, Yan; Zhang, Meng; Huang, Ying; Wu, Chen [State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Department of Etiology and Carcinogenesis (Beijing Key Laboratory for Carcinogenesis and Cancer Prevention), Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Xiao, Zefen, E-mail: xiaozefen@sina.com [Department of Radiation Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Tan, Wen, E-mail: tanwen@cicams.ac.cn [State Key Laboratory of Molecular Oncology, Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); Department of Etiology and Carcinogenesis (Beijing Key Laboratory for Carcinogenesis and Cancer Prevention), Cancer Institute and Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing (China); and others

    2015-09-01

    Purpose: To investigate whether single nucleotide polymorphisms (SNPs) in the ataxia telangiectasia mutated (ATM) gene are associated with survival in patients with esophageal squamous cell carcinoma (ESCC) receiving radiation therapy or chemoradiation therapy or surgery only. Methods and Materials: Four tagSNPs of ATM were genotyped in 412 individuals with clinical stage III or IV ESCC receiving radiation therapy or chemoradiation therapy, and in 388 individuals with stage I, II, or III ESCC treated with surgery only. Overall survival time of ESCC among different genotypes was estimated by Kaplan-Meier plot, and the significance was examined by log-rank test. The hazard ratios (HRs) and 95% confidence intervals (CIs) for death from ESCC among different genotypes were computed by a Cox proportional regression model. Results: We found 2 SNPs, rs664143 and rs664677, associated with survival time of ESCC patients receiving radiation therapy. Individuals with the rs664143A allele had poorer median survival time compared with the rs664143G allele (14.0 vs 20.0 months), with the HR for death being 1.45 (95% CI 1.12-1.89). Individuals with the rs664677C allele also had worse median survival time than those with the rs664677T allele (14.0 vs 23.5 months), with the HR of 1.57 (95% CI 1.18-2.08). Stratified analysis showed that these associations were present in both stage III and IV cancer and different radiation therapy techniques. Significant associations were also found between the SNPs and locosregional progression or progression-free survival. No association between these SNPs and survival time was detected in ESCC patients treated with surgery only. Conclusion: These results suggest that the ATM polymorphisms might serve as independent biomarkers for predicting prognosis in ESCC patients receiving radiation therapy.

  16. The role of ATM in maintenance of telomeres in Arabidopsis thaliana

    Czech Academy of Sciences Publication Activity Database

    Široký, Jiří; Mokroš, Petr; Vespa, L.; Shippen, D.

    Southampton, 2006. C2.37-C2.37. [Cell Cycle Symposium. 03.07.2006-06.07.2006, Southampton] R&D Projects: GA ČR(CZ) GA522/06/0380 Institutional research plan: CEZ:AV0Z50040507 Keywords : Arabidopsis thaliana * DNA repair * ataxia telangiectasia mutated Subject RIV: BO - Biophysics

  17. Loss of ATM kinase activity leads to embryonic lethality in mice

    DEFF Research Database (Denmark)

    Daniel, J.A.; Pellegrini, M.; Filsuf, D.;

    2012-01-01

    Ataxia telangiectasia (A-T) mutated (ATM) is a key deoxyribonucleic acid (DNA) damage signaling kinase that regulates DNA repair, cell cycle checkpoints, and apoptosis. The majority of patients with A-T, a cancer-prone neurodegenerative disease, present with null mutations in Atm. To determine...

  18. Friend leukemia virus transformed cells exposed to microgravity in the presence of DMSO (7-IML-1)

    Science.gov (United States)

    Cogoli, Augusto

    1992-01-01

    The purpose of this experiment is to study the adaptation of living cells to microgravity. The in vitro transformation of Friend cells by Dimethylsufoxide (DMSO) is a good model for the study of cell differentiation and protein biosynthesis. Cultures of cells will be prepared shortly before launch. Once in space, transformation will be induced by injection of DMSO. One set of cultures will be chemically fixed with glutaraldehyde for electron microscope investigations; another set will be preserved for determining the amount of hemogloben produced and the extent of cell proliferation.

  19. A nitroimidazole derivative, PR-350, enhances the killing of pancreatic cancer cells exposed to high-dose irradiation under hypoxia

    International Nuclear Information System (INIS)

    The radiosensitizing effects of PR-350, a nitroimidazole derivative, were examined concerning the cell killing of human pancreatic cancer cell lines exposed to high doses of gamma-ray irradiation in vitro. The percentages of dead cells were analyzed with a multiwell plate reader to measure the fluorescence intensity of propidium iodide before and after a digitonin treatment. The sensitizing effect of PR-350 on cell killing by high-dose irradiation was confirmed by time-course, dose-dependency, and microscopic observations. In five of seven pancreatic cancer cell lines in which the number of dead cells was determined 5 days after 30 Gy irradiation in the presence of PR-350, the number was significantly increased under hypoxic conditions, but not under aerobic conditions. The selective radiosensitive effect of PR-350 on hypoxic cells was also confirmed by flow cytometry. The results indicate that PR-350 can enhance the killing of pancreatic cancer cells by high-dose irradiation under hypoxia, which supports its clinical radiosensitizing effects when administered during intraoperative irradiation to pancreatic cancer. (author)

  20. Naphthalimides Induce G2 Arrest Through the ATM-Activated Chk2-Executed Pathway in HCT116 Cells

    Directory of Open Access Journals (Sweden)

    Hong Zhu

    2009-11-01

    Full Text Available Naphthalimides, particularly amonafide and 2-(2-dimethylamino-6-thia-2-aza-benzo[def]chrysene-1,3-diones (R16, have been identified to possess anticancer activities and to induce G2-M arrest through inhibiting topoisomerase II accompanied by Chk1 degradation. The current study was designed to precisely dissect the signaling pathway(s responsible for the naphthalimide-induced cell cycle arrest in human colon carcinoma HCT116 cells. Using phosphorylated histone H3 and mitotic protein monoclonal 2 as mitosis markers, we first specified the G2 arrest elicited by the R16 and amonafide. Then, R16 and amonafide were revealed to induce phosphorylation of the DNA damage sensor ataxia telangiectasia-mutated (ATM responding to DNA double-strand breaks (DSBs. Inhibition of ATM by both the pharmacological inhibitor caffeine and the specific small interference RNA (siRNA rescued the G2 arrest elicited by R16, indicating its ATM-dependent characteristic. Furthermore, depletion of Chk2, but not Chk1 with their corresponding siRNA, statistically significantly reversed the R16- and amonafide-triggered G2 arrest. Moreover, the naphthalimides phosphorylated Chk2 in an ATM-dependent manner but induced Chk1 degradation. These data indicate that R16 and amonafide preferentially used Chk2 as evidenced by the differential ATM-executed phosphorylation of Chk1 and Chk2. Thus, a clear signaling pathway can be established, in which ATM relays the DNA DSBs signaling triggered by the naphthalimides to the checkpoint kinases, predominantly to Chk2,which finally elicits G2 arrest. The mechanistic elucidation not only favors the development of the naphthalimides as anticancer agents but also provides an alternative strategy of Chk2 inhibition to potentiate the anticancer activities of these agents.

  1. Radiosensitizing effect of Chitosan on HeLa and LN 18 brain tumor cells exposed to electron beam radiation

    International Nuclear Information System (INIS)

    Chitosan has been widely used for multiple applications because it is a non-toxic biocompatible, biodegradable, and adsorptive material. A previous study has shown that low-molecular-weight chitosan (LMWC) exerts a cytotoxic effect on oral cancer cells. Although a higher concentration of LMWC in comparison to cisplatin was needed in order to kill cancer cells, it was relatively less cytotoxic to non-cancer cells. Some of the well known anticancer drugs have the property of sensitizing the cell to radiation, which will be more applicable during combination therapy of cancer. The present study was undertaken to find the radiosensitizing effect of chitosan on Hela and Brain tumor (LN18) cells against electron beam radiation (EBR). Both the cancer cell lines, Hela and LN 18 were treated with different concentration of chitosan (50 and 100 μg/ml) pre and post exposure to 4 Gy EBR. The percentage of cell viability, percentage of apoptosis and ssDNA damage in the treated cells were assessed by MTT assay, DNA diffusion assay and comet assay respectively. The obtained results showed 62.1315.08 and 65.2412.45 percent Hela and LN 18 viable cells at 24 hour after the exposure to 4 Gy EBR. The percentage of viability was found to be decreased in cells exposed to EBR in the presence of chitosan. Supporting to this, percentage of apoptotic cells was found to be more in treated groups (28.1314.34 and 25.1313.76) when compared with control (23.1911.07 and 20.7914.86). Treatment of HeLa and LN18 before and after the exposure of EBR showed significantly (P<0.05) more frequency of micronucleus and % of DNA damage than the 4 Gy EBR control group. These results conclude the sensitizing effect of chitosan on cancer cell line against EBR exposure. (author)

  2. FGF2 mediates DNA repair in epidermoid carcinoma cells exposed to ionizing radiation

    International Nuclear Information System (INIS)

    Fibroblast growth factor 2 (FGF2) is a well-known survival factor. However, its role in DNA repair is poorly documented. The present study was designed to investigate in epidermoid carcinoma cells the potential role of FGF2 in DNA repair. The side population (SP) with cancer stem cell-like properties and the main population (MP) were isolated from human A431 squamous carcinoma cells. Radiation-induced DNA damage and repair were assessed using the alkaline comet assay. FGF2 expression was quantified by enzyme linked immunosorbent assay (ELISA). SP cells exhibited rapid repair of radiation induced DNA damage and a high constitutive level of nuclear FGF2. Blocking FGF2 signaling abrogated the rapid DNA repair. In contrast, in MP cells, a slower repair of damage was associated with low basal expression of FGF2. Moreover, the addition of exogenous FGF2 accelerated DNA repair in MP cells. When irradiated, SP cells secreted FGF2, whereas MP cells did not. FGF2 was found to mediate DNA repair in epidermoid carcinoma cells. We postulate that carcinoma stem cells would be intrinsically primed to rapidly repair DNA damage by a high constitutive level of nuclear FGF2. In contrast, the main population with a low FGF2 content exhibits a lower repair rate which can be increased by exogenous FGF2. (authors)

  3. Raman spectroscopy of single human tumour cells exposed to ionizing radiation in vitro

    International Nuclear Information System (INIS)

    This work investigates the capability of Raman spectroscopy (RS) to study the effects of ionizing radiation on single human tumour cells. Prostate tumour cells (cell line DU145) are cultured in vitro and irradiated to doses between 15 and 50 Gy with single fractions of 6 MV photons. Single-cell Raman spectra are acquired from irradiated and unirradiated cultures up to 5 days post-irradiation. Principal component analysis is used to distinguish the uniquely radiation-induced spectral changes from inherent sources of spectral variability arising from cell cycle differences and other known factors. We observe uniquely radiation-induced spectral changes which are correlated with both the irradiated dose and the incubation time post-irradiation. The spectral changes induced by radiation arise from biochemical differences in lipids, nucleic acids, amino acids and conformational protein structures between irradiated and unirradiated cells. To our knowledge, this study is the first use of RS to observe radiation-induced biochemical differences in single cells, and is the first use of vibrational spectroscopy to observe uniquely radiation-induced biochemical differences in single cells independent of concurrent cell-cycle- or cell-death-related processes.

  4. Area Expansivity Moduli of Regenerating Plant Protoplast Cell Walls Exposed to Shear Flows

    Science.gov (United States)

    Fujimura, Yuu; Iino, Masaaki; Watanabe, Ugai

    2005-05-01

    To control the elasticity of the plant cell wall, protoplasts isolated from cultured Catharanthus roseus cells were regenerated in shear flows of 115 s-1 (high shear) and 19.2 s-1 (low shear, as a control). The surface area expansivity modulus and the surface breaking strength of these regenerating protoplasts were measured by a micropipette aspiration technique. Cell wall synthesis was also measured using a cell wall-specific fluorescent dye. High shear exposure for 3 h doubled both the surface area modulus and breaking strength observed under low shear, significantly decreased cell wall synthesis, and roughly quadrupled the moduli of the cell wall. Based on the cell wall synthesis data, we estimated the three-dimensional modulus of the cell wall to be 4.1± 1.2 GPa for the high shear, and 0.35± 0.2 GPa for the low shear condition, using the surface area expansivity modulus divided by the cell wall thickness, which is identical with the Young’s modulus divided by 2(1-σ), where σ is Poisson's ratio. We concluded that high shear exposure considerably strengthens the newly synthesized cell wall.

  5. Analysis of Pseudomonas aeruginosa cell envelope proteome by capture of surface-exposed proteins on activated magnetic nanoparticles.

    Directory of Open Access Journals (Sweden)

    Davide Vecchietti

    Full Text Available We report on specific magneto-capturing followed by Multidimensional Protein Identification Technology (MudPIT for the analysis of surface-exposed proteins of intact cells of the bacterial opportunistic pathogen Pseudomonas aeruginosa. The magneto-separation of cell envelope fragments from the soluble cytoplasmic fraction allowed the MudPIT identification of the captured and neighboring proteins. Remarkably, we identified 63 proteins captured directly by nanoparticles and 67 proteins embedded in the cell envelope fragments. For a high number of proteins, our analysis strongly indicates either surface exposure or localization in an envelope district. The localization of most identified proteins was only predicted or totally unknown. This novel approach greatly improves the sensitivity and specificity of the previous methods, such as surface shaving with proteases that was also tested on P. aeruginosa. The magneto-capture procedure is simple, safe, and rapid, and appears to be well-suited for envelope studies in highly pathogenic bacteria.

  6. The influence of ATM, ATR, DNA-PK inhibitors on the cytotoxic and genotoxic effects of dibenzo[def,p]chrysene on human hepatocellular cancer cell line HepG2.

    Science.gov (United States)

    Spryszyńska, Sylwia; Smok-Pieniążek, Anna; Ferlińska, Magdalena; Roszak, Joanna; Nocuń, Marek; Stępnik, Maciej

    2015-09-01

    The effect of inhibitors of phosphatidylinositol-3-kinase related kinases (PIKK): ataxia-telangiectasia mutated (ATM), ATM- and Rad3-related (ATR) and DNA-dependent protein kinase (DNA-PK) on the response of HepG2 human liver cancer cells to dibenzo[def,p]chrysene (DBC) was investigated. High cytotoxicity of DBC (IC50=0.1μM) was observed after 72h incubation. PIKK inhibitors: KU55933 (5μM), NU7026 (10μM) or caffeine (1 and 2mM) when used alone did not significantly influence the cytotoxicity. However, two combinations: KU55933/NU7026 and caffeine/NU7026 significantly increased HepG2 viability (by 25%) after treatment with DBC at 0.5μM. The cytoprotective effect was confirmed by cell cycle and apoptosis/necrosis analysis. DNA damage level after exposure to DBC assessed by comet assay (single strand breaks) showed a long persistence and significant decrease after incubation of the cells in the presence the inhibitors (the combination of KU55933+NU7026 showed the strongest effect). Weak induction of reactive oxygen species (ROS) by DBC (0.5μM) was observed. Although, KU55933 and NU7026 when used alone did not increase ROS levels in the cells, their combination induced the ROS increase and moderately enhanced ROS generation by DBC. We propose a mechanism how cells with damaged DNA after exposure to DBC and under the condition of PIKK inhibition, may be at higher risk of undergoing malignant transformation. PMID:26338538

  7. Anti-Inflammatory Effects of Pomegranate Peel Extract in THP-1 Cells Exposed to Particulate Matter PM10

    Directory of Open Access Journals (Sweden)

    Soojin Park

    2016-01-01

    Full Text Available Epidemiological and experimental evidence support health risks associated with the exposure to airborne particulate matter with a diameter of <10 μM (PM10. PM10 stimulates the production of reactive oxygen species (ROS and inflammatory mediators. Thus, we assumed that natural antioxidants might provide health benefits attenuating hazardous effects of PM10. In the present study, we examined the effects of pomegranate peel extract (PPE on THP-1 monocytic cells exposed to PM10. PM10 induced cytotoxicity and the production of ROS. It also increased the expression and secretion of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α, interleukin-1β (IL-1β, and monocyte chemoattractant protein-1 (MCP-1, and cell adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1. PPE at 10–100 μg mL−1 attenuated the production of ROS and the expression of TNF-α, IL-1β, MCP-1, and ICAM-1, but not VCAM-1, in THP-1 cells stimulated by PM10 (100 μg mL−1. PPE also attenuated the adhesion of PM10-stimulated THP-1 cells to EA.hy926 endothelial cells. PPE constituents, punicalagin and ellagic acid, attenuated PM10-induced monocyte adhesion to endothelial cells, and punicalagin was less cytotoxic compared to ellagic acid. The present study suggests that PPE and punicalagin may be useful in alleviating inflammatory reactions due to particulate matter.

  8. Anti-Inflammatory Effects of Pomegranate Peel Extract in THP-1 Cells Exposed to Particulate Matter PM10

    Science.gov (United States)

    Park, Soojin; Seok, Jin Kyung; Kwak, Jun Yup; Suh, Hwa-Jin; Kim, Young Mi; Boo, Yong Chool

    2016-01-01

    Epidemiological and experimental evidence support health risks associated with the exposure to airborne particulate matter with a diameter of pomegranate peel extract (PPE) on THP-1 monocytic cells exposed to PM10. PM10 induced cytotoxicity and the production of ROS. It also increased the expression and secretion of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and monocyte chemoattractant protein-1 (MCP-1), and cell adhesion molecules, such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). PPE at 10–100 μg mL−1 attenuated the production of ROS and the expression of TNF-α, IL-1β, MCP-1, and ICAM-1, but not VCAM-1, in THP-1 cells stimulated by PM10 (100 μg mL−1). PPE also attenuated the adhesion of PM10-stimulated THP-1 cells to EA.hy926 endothelial cells. PPE constituents, punicalagin and ellagic acid, attenuated PM10-induced monocyte adhesion to endothelial cells, and punicalagin was less cytotoxic compared to ellagic acid. The present study suggests that PPE and punicalagin may be useful in alleviating inflammatory reactions due to particulate matter. PMID:27247608

  9. Gene expression signatures in CD34+-progenitor-derived dendritic cells exposed to the chemical contact allergen nickel sulfate

    International Nuclear Information System (INIS)

    The detection of the sensitizing potential of chemicals is of great importance to industry. A promising in vitro alternative to the currently applied animal assays for sensitization testing makes use of dendritic cells (DCs) that have the capability to process and present antigens to naive T cells and induce their proliferation. Here, we studied changes in gene expression profiles after exposing DCs to the contact allergen nickel sulfate. CD34+-progenitor-derived DCs, initiated from 3 different donors, were exposed to 60 μM nickel sulfate, during 0.5, 1, 3, 6, 12 and 24 h. cDNA microarrays were used to assess the transcriptional activity of about 11,000 genes. Significant changes in the expression of 283 genes were observed; 178 genes were up-regulated and 93 down-regulated. These genes were involved in metabolism, cell structure, immune response, transcription, signal transduction, transport, and apoptosis. No functional information was found for 74 genes. Real-time RT-PCR was used to confirm the microarray results of 12 genes. In addition, 3 DC maturation markers not present on the microarrays (DEC205, DC LAMP and CCR7) were analyzed using real-time RT-PCR and found to be up-regulated at several time points. Our data indicate that a broad range of biological processes is influenced by nickel. Some processes are clearly linked to the immune response and DC maturation, others may indicate a toxic effect of nickel

  10. Apoptosis in HeLa cell exposed to different dose, dose-rate of 32P β-irradiation and the correlation with cell-killing efficacy

    International Nuclear Information System (INIS)

    In an attempt to elucidate some aspects of the radiobiological basis of targeted radiotherapy in oncology, the apoptosis occurred have been studied in Hela cell lines after exposing to different doses and dose-rate radiation of 32P and the relationship between apoptosis occurred and the capacity of cell proliferation, which might be of help to the understanding of targeted radiotherapy. Asynchronous Hela cells were exposed to β radiation from 32P absorbed in filter papers which were put closely under culture dishes of growing monolayer of Hela cell. The radiation response characteristics to different dose, dose-rate and radiation time were evaluated through cell-proliferation assessed by the colony-forming assay, cell cycle perturbation studied by flow cytometry and quantity analysis of apoptosis analyzed by flow cytometry and fluorescence microscopy. Morphological and flow cytometry analysis showed a delayed apoptosis. The programmed cell death approached a plateau between 48-72h post-irradiation. Electron and fluorescence microscopic studies showed the presence of morphologically apoptotic cells. Single dose radiation showed a higher apoptosis ratio than multiple low dose radiation, which did not correlate with clonal-forming assay, suggesting apoptosis ratio at a near time point post-irradiation is not a convincing indicator of radiation efficacy in the current experimental setting

  11. Structural damage of chicken red blood cells exposed to platinum nanoparticles and cisplatin

    DEFF Research Database (Denmark)

    Kutwin, Marta; Sawosz, Ewa; Jaworski, Sławomir; Kurantowicz, Natalia; Strojny, Barbara; Chwalibog, André

    2014-01-01

    platinum nanoparticles (NP-Pt) and cisplatin with blood compartments are important for future applications. This study investigated structural damage, cell membrane deformation and haemolysis of chicken embryo red blood cells (RBC) after treatment with cisplatin and NP-Pt. Cisplatin (4 μg/ml) and NP-Pt (2...

  12. Transcriptome analysis of the human T lymphocyte cell line Jurkat and human peripheral blood mononuclear cells exposed to deoxynivalenol (DON): New mechanistic insights

    Energy Technology Data Exchange (ETDEWEB)

    Katika, Madhumohan R. [RIKILT-Institute of Food Safety, Wageningen University and Research Centre, Wageningen (Netherlands); Department of Health Risk Analysis and Toxicology, Maastricht University (Netherlands); Netherlands Toxicogenomics Centre (Netherlands); Hendriksen, Peter J.M. [RIKILT-Institute of Food Safety, Wageningen University and Research Centre, Wageningen (Netherlands); Netherlands Toxicogenomics Centre (Netherlands); Shao, Jia [RIKILT-Institute of Food Safety, Wageningen University and Research Centre, Wageningen (Netherlands); Department of Health Risk Analysis and Toxicology, Maastricht University (Netherlands); Netherlands Toxicogenomics Centre (Netherlands); Loveren, Henk van [Department of Health Risk Analysis and Toxicology, Maastricht University (Netherlands); National Institute for Public Health and the Environment (RIVM), Bilthoven (Netherlands); Netherlands Toxicogenomics Centre (Netherlands); Peijnenburg, Ad, E-mail: ad.peijnenburg@wur.nl [RIKILT-Institute of Food Safety, Wageningen University and Research Centre, Wageningen (Netherlands); Netherlands Toxicogenomics Centre (Netherlands)

    2012-10-01

    Deoxynivalenol (DON) or vomitoxin is a commonly encountered type-B trichothecene mycotoxin, produced by Fusarium species predominantly found in cereals and grains. DON is known to exert toxic effects on the gastrointestinal, reproductive and neuroendocrine systems, and particularly on the immune system. Depending on dose and exposure time, it can either stimulate or suppress immune function. The main objective of this study was to obtain a deeper insight into DON-induced effects on lymphoid cells. For this, we exposed the human T-lymphocyte cell line Jurkat and human peripheral blood mononuclear cells (PBMCs) to various concentrations of DON for various times and examined gene expression changes by DNA microarray analysis. Jurkat cells were exposed to 0.25 and 0.5 μM DON for 3, 6 and 24 h. Biological interpretation of the microarray data indicated that DON affects various processes in these cells: It upregulates genes involved in ribosome structure and function, RNA/protein synthesis and processing, endoplasmic reticulum (ER) stress, calcium-mediated signaling, mitochondrial function, oxidative stress, the NFAT and NF-κB/TNF-α pathways, T cell activation and apoptosis. The effects of DON on the expression of genes involved in ER stress, NFAT activation and apoptosis were confirmed by qRT-PCR. Other biochemical experiments confirmed that DON activates calcium-dependent proteins such as calcineurin and M-calpain that are known to be involved in T cell activation and apoptosis. Induction of T cell activation was also confirmed by demonstrating that DON activates NFATC1 and induces its translocation from the cytoplasm to the nucleus. For the gene expression profiling of PBMCs, cells were exposed to 2 and 4 μM DON for 6 and 24 h. Comparison of the Jurkat microarray data with those obtained with PBMCs showed that most of the processes affected by DON in the Jurkat cell line were also affected in the PBMCs. -- Highlights: ► The human T cell line Jurkat and human

  13. miRNA regulation of cytotoxic effects in mouse Sertoli cells exposed to nonylphenol

    Directory of Open Access Journals (Sweden)

    Kim Seung Jun

    2011-09-01

    Full Text Available Abstract Background It is known that some environmental chemicals affect the human endocrine system. The harmful effects of endocrine disrupting chemical (EDC nonylphenol (NP have been studied since the 1980s. It is known that NP adversely affects physiological functions by mimicking the natural hormone 17 beta-estradiol. In the present study, we analyzed the expression of miRNAs and their target genes in mouse Sertoli TM4 cells to better understand the regulatory roles of miRNAs on Sertoli cells after NP exposure. Methods Mouse TM4 Sertoli cells were treated with NP for 3 or 24 h, and global gene and miRNA expression were analyzed using Agilent mouse whole genome and mouse miRNA v13 arrays. Results We identified genes that were > 2-fold differentially expressed in NP-treated cells and control cells (P Ppara may regulate the expression of certain miRNAs, including miR-378, miR-125a-3p miR-20a, miR-203, and miR-101a, after exposure to NP. Additionally, comprehensive analysis of predicted target genes for miRNAs showed that the expression of genes with roles in cell proliferation, the cell cycle, and cell death were regulated by miRNA in NP-treated TM4 cells. Levels of expression of the miRNAs miR-135a* and miR-199a-5p were validated by qRT-PCR. Finally, miR-135a* target gene analysis suggests that the generation of reactive oxygen species (ROS following exposure to NP exposure may be mediated by miR-135a* through regulation of the Wnt/beta-catenin signaling pathway. Conclusions Collectively, these data help to determine NP's actions on mouse TM4 Sertoli cells and increase our understanding of the molecular mechanisms underlying the adverse effects of xenoestrogens on the reproductive system.

  14. Antigen-presenting cells exposed to Lactobacillus acidophilus NCFM, Bifidobacterium bifidum BI-98, and BI-504 reduce regulatory T cell activity

    DEFF Research Database (Denmark)

    Schmidt, Esben Gjerløff Wedebye; Claesson, Mogens Helweg; Jensen, Simon Skjøde;

    2010-01-01

    enteroantigen-presenting cells (APC) and CD4(+)CD25(+) T-regulatory cells (Tregs) in splenocyte-T cell proliferation assays. METHODS:: Splenocytes exposed to enteroantigen +/- probiotics were used to stimulate cultured CD4(+)CD25(-) T cells to which titrated numbers of Tregs were added. Cytokine assays were...... performed by use of neutralizing antibodies and ELISA. RESULTS:: Exposure of APCs to enteroantigens and the series of probiotic strains mentioned above did not influence the stimulatory capacity of APCs on proliferative enteroantigen-specific T cells. However, exposure to B. bifidum BI-98, BI-504 and L....... acidophilus NCFM consistently reduced the suppressive activity of Tregs. The suppressive activity was analyzed using fractionated components of the probiotics, and showed that a component of the cell wall is responsible for the decreased Treg activity in the system. The probiotic-induced suppression of Treg...

  15. Low-level laser therapy: Effects on human face aged skin and cell viability of HeLa cells exposed to UV radiation

    Directory of Open Access Journals (Sweden)

    Mezghani Sana

    2015-01-01

    Full Text Available Chronic and excessive exposure to UV radiation leads to photoaging and photocarcinogenesis. Adequate protection of the skin against the deleterious effects of UV irradiation is essential. Low-level laser therapy (LLLT is a light source in the red to near-infrared range that has been accepted in a variety of medical applications. In this study, we explored the effect of LLLT in human face aged skin and the cell viability of HeLa cells exposed to UV radiation. We found that LLLT significantly reduced visible wrinkles and the loss of firmness of facial skin in aging subjects. Additionally, treatment of cultured HeLa cells with LLLT prior to or post UVA or UVB exposure significantly protected cells from UV-mediated cell death. All results showed the beneficial effects of LLLT on relieving signs of skin aging and its prevention and protection of the cell viability against UV-induced damage.

  16. Characteristics of human CD34+ cells exposed to ionizing radiation under cytokine-free conditions

    International Nuclear Information System (INIS)

    To clarify the mechanisms underlying radiation-induced hematopoietic stem cell death, we investigated the effects of excessive ionizing radiation on the clonogenic potential of CD34+ cells obtained from human umbilical cord blood under cytokine-free conditions. The CD34+ cells were X-ray-irradiated (up to 2 Gy) and were cultured for 0-48 h under cytokine-free conditions. At various time-points, the CD34+ cells were investigated for survival, clonogenic potential and the generation of mitochondrial superoxide. At 12 h after X-ray irradiation, the number of viable cells had decreased to ∼70-80% compared with the 0-h non-irradiated control, whereas the clonogenic potential in the X-ray-irradiated cells had decreased to ∼50%-60% compared with the 0-h non-irradiated control. Furthermore, significant generation of mitochondrial superoxide was observed at 6 h, and reached a maximum value between 12 and 24 h after X-ray irradiation. However, no significant differences were observed between non-irradiated and X-ray-irradiated cells in terms of the generation of reactive oxygen species or in the intracellular mitochondrial contents. In addition, a cDNA microarray analysis showed that the majority of the altered genes in the CD34+ cells at 6 h after X-ray irradiation were apoptosis-related genes. These results suggest the possibility that the elimination of the clonogenic potentials of CD34+ cells involves the generation of mitochondrial superoxide induced by ionizing radiation. (author)

  17. Inter- and Intra-Chromosomal Aberrations in Human Cells Exposed in vitro to High and Low LET Radiations

    Science.gov (United States)

    Hada, M.; Wilkins, R.; Saganti, P. B.; Gersey, B.; Cucinotta, F. A.; Wu, H.

    2006-01-01

    Energetic heavy ions pose a health risk to astronauts in extended ISS and future Mars missions. High-LET heavy ions are particularly effective in causing various biological effects including cell inactivation, genetic mutations and cancer induction. Most of these biological endpoints are closely related to chromosomal damage, which can be utilized as a biomarker for radiation insults. Previously, we had studied chromosome aberrations in human lymphocytes and fibroblasts induced by both low- and high-LET radiation using FISH and multicolor fluorescence in situ hybridization (mFISH) techniques. In this study, we exposed human epithelial cells in vitro to gamma rays and energetic particles of varying types and energies and dose rates, and analyzed chromosomal damages using the multicolor banding in situ hybridization (mBAND) procedure. Confluent human epithelial cells (CH184B5F5/M10) were exposed to energetic heavy ions at NASA Space Radiation Laboratory (NSRL) at the Brookhaven National Laboratory, high energy neutron at the Los Alamos Nuclear Science Center (LANSCE) or Cs-137-gamma radiation source at the University of Texas, MD Anderson Cancer Center. After colcemid and Calyculin A treatment, cells were fixed and painted with XCyte3 mBAND kit (MetaSystems) and chromosome aberrations were analyzed with mBAND analysis system (MetaSystems). With this technique, individually painted chromosomal bands on one chromosome allowed the identification of interchromosomal aberrations (translocation to unpainted chromosomes) and intrachromosomal aberrations (inversions and deletions within a single painted chromosome). The results of the mBAND study showed a higher ratio of inversion involved with interchromosomal exchange in heavy ions compared to -ray irradiation. Analysis of chromosome aberrations using mBAND has the potential to provide useful information on human cell response to space-like radiation.

  18. DNA damage and apoptosis of endometrial cells cause loss of the early embryo in mice exposed to carbon disulfide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bingzhen [Department of Epidemiology and Health Statistics, School of Public Health, Shandong University, Jinan (China); Shen, Chunzi [Centers for Disease Control and Prevention, Zibo (China); Yang, Liu; Li, Chunhui; Yi, Anji [Department of Epidemiology and Health Statistics, School of Public Health, Shandong University, Jinan (China); Wang, Zhiping, E-mail: zhipingw@sdu.edu.cn [Department of Epidemiology and Health Statistics, School of Public Health, Shandong University, Jinan (China)

    2013-12-01

    Carbon disulfide (CS{sub 2}) may lead to spontaneous abortion and very early pregnancy loss in women exposed in the workplace, but the mechanism remains unclear. We designed an animal model in which gestating Kunming strain mice were exposed to CS{sub 2} via i.p. on gestational day 4 (GD4). We found that the number of implanted blastocysts on GD8 was significantly reduced by each dose of 0.1 LD{sub 50} (157.85 mg/kg), 0.2 LD{sub 50} (315.7 mg/kg) and 0.4 LD{sub 50} (631.4 mg/kg). In addition, both the level of DNA damage and apoptosis rates of endometrial cells on GD4.5 were increased, showed definite dose–response relationships, and inversely related to the number of implanted blastocysts. The expressions of mRNA and protein for the Bax and caspase-3 genes in the uterine tissues on GD4.5 were up-regulated, while the expressions of mRNA and protein for the Bcl-2 gene were dose-dependently down-regulated. Our results indicated that DNA damage and apoptosis of endometrial cells were important reasons for the loss of implanted blastocysts induced by CS{sub 2}. - Highlights: • We built an animal model of CS2 exposure during blastocyst implantation. • Endometrial cells were used in the comet assay to detect DNA damage. • CS2 exposure caused DNA damage and endometrial cell apoptosis. • DNA damage and endometrial cell apoptosis were responsible for embryo loss.

  19. Rcan1-1L overexpression induces mitochondrial autophagy and improves cell survival in angiotensin II-exposed cardiomyocytes

    International Nuclear Information System (INIS)

    Mitochondrial autophagy is an important adaptive stress response and can be modulated by various key molecules. A previous study found that the regulator of calcineurin 1-1L (Rcan1-1L) may regulate mitochondrial autophagy and cause mitochondria degradation in neurocytes. However, the effect of Rcan1-1L on cardiomyocytes has not been determined. In the present study, we aimed to investigate the role of Rcan1-1L in angiotensin II (Ang II)-exposed human cardiomyocytes. Above all, Human adult cardiac myocytes (HACMs) were exposed to 200 nmol/L Ang II for 4 days. Enhanced H2O2 production, cytochrome C release and mitochondrial permeability were observed in these cells, which were blocked by valsartan. Consistently, Ang II exposure significantly reduced cardiomyocyte viability. However, transfection of Rcan1-1L vector promoted cell viability and ameliorated the apoptosis caused by Ang II. Rcan1-1L clearly promoted mitochondrial autophagy in HACMs, with elevated autophagy protein (ATG) 5 and light chain 3 (LC3) expression. Transient mitochondrial biogenesis and reduced cytochrome C release was also induced by Rcan1-1L. Additionally, Rcan1-1L significantly inhibited calcineurin/nuclear factor of activated T cells (NFAT) signaling. We thus conclude that Rcan1-1L may play a protective role in Ang II-treated cardiomyocytes through the induction of mitochondrial autophagy, and may be an alternative method of cardiac protection. - Highlights: • Transfection of Rcan1-1L into HACMs promoted cell viability and reduced apoptosis. • Transfection of Rcan1-1L promoted mitochondrial autophagy in HACMs. • Rcan1-1L inhibited the calcineurin/nuclear factor of activated T cells signaling

  20. Rcan1-1L overexpression induces mitochondrial autophagy and improves cell survival in angiotensin II-exposed cardiomyocytes

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Hongyan; Li, Yongqiang; Yan, Lijie; Yang, Haitao; Wu, Jintao; Qian, Peng; Li, Bing; Wang, Shanling, E-mail: shanglingwang@126.com

    2015-07-01

    Mitochondrial autophagy is an important adaptive stress response and can be modulated by various key molecules. A previous study found that the regulator of calcineurin 1-1L (Rcan1-1L) may regulate mitochondrial autophagy and cause mitochondria degradation in neurocytes. However, the effect of Rcan1-1L on cardiomyocytes has not been determined. In the present study, we aimed to investigate the role of Rcan1-1L in angiotensin II (Ang II)-exposed human cardiomyocytes. Above all, Human adult cardiac myocytes (HACMs) were exposed to 200 nmol/L Ang II for 4 days. Enhanced H{sub 2}O{sub 2} production, cytochrome C release and mitochondrial permeability were observed in these cells, which were blocked by valsartan. Consistently, Ang II exposure significantly reduced cardiomyocyte viability. However, transfection of Rcan1-1L vector promoted cell viability and ameliorated the apoptosis caused by Ang II. Rcan1-1L clearly promoted mitochondrial autophagy in HACMs, with elevated autophagy protein (ATG) 5 and light chain 3 (LC3) expression. Transient mitochondrial biogenesis and reduced cytochrome C release was also induced by Rcan1-1L. Additionally, Rcan1-1L significantly inhibited calcineurin/nuclear factor of activated T cells (NFAT) signaling. We thus conclude that Rcan1-1L may play a protective role in Ang II-treated cardiomyocytes through the induction of mitochondrial autophagy, and may be an alternative method of cardiac protection. - Highlights: • Transfection of Rcan1-1L into HACMs promoted cell viability and reduced apoptosis. • Transfection of Rcan1-1L promoted mitochondrial autophagy in HACMs. • Rcan1-1L inhibited the calcineurin/nuclear factor of activated T cells signaling.

  1. Chemoprotective effects of curcumin in esophageal epithelial cells exposed to bile acids

    Institute of Scientific and Technical Information of China (English)

    Matthew; R; Bower; Harini; S; Aiyer; Robert; CG; Martin

    2010-01-01

    AIM:To investigate the ability of curcumin to counteract the impact of bile acids on gene expression of esophageal epithelial cells.METHODS:An esophageal epithelial cell line(HET1A)was treated with curcumin in the presence of deoxycholic acid.Cell proliferation and viability assays were used to establish an appropriate dose range for curcumin.The combined and individual effects of curcumin and bile acid on cyclooxygenase-2(COX-2)and superoxide dismutase(SOD-1 and SOD-2)gene expression were also assessed.RES...

  2. Glucagon-Like Peptide-1 Triggers Protective Pathways in Pancreatic Beta-Cells Exposed to Glycated Serum

    Directory of Open Access Journals (Sweden)

    Alessandra Puddu

    2013-01-01

    Full Text Available Advanced glycation end products (AGEs might play a pathophysiological role in the development of diabetes and its complications. AGEs negatively affect pancreatic beta-cell function and the expression of transcriptional factors regulating insulin gene. Glucagon-like peptide-1 (GLP-1, an incretin hormone that regulates glucose homeostasis, might counteract the harmful effects of AGEs on the beta cells in culture. The aim of this study was to identify the intracellular mechanisms underlying GLP-1-mediated protection from AGE-induced detrimental activities in pancreatic beta cells. HIT-T15 cells were cultured for 5 days with glycated serum (GS, consisting in a pool of AGEs, in the presence or absence of 10 nmol/L GLP-1. After evaluation of oxidative stress, we determined the expression and subcellular localization of proteins involved in maintaining redox balance and insulin gene expression, such as nuclear factor erythroid-derived 2 (Nrf2, glutathione reductase, PDX-1, and MafA. Then, we investigated proinsulin production. The results showed that GS increased oxidative stress, reduced protein expression of all investigated factors through proteasome activation, and decreased proinsulin content. Furthermore, GS reduced ability of PDX-1 and MafA to bind DNA. Coincubation with GLP-1 reversed these GS-mediated detrimental effects. In conclusion, GLP-1, protecting cells against oxidants, triggers protective intercellular pathways in HIT-T15 cells exposed to GS.

  3. ATM Polymorphisms Predict Severe Radiation Pneumonitis in Patients With Non-Small Cell Lung Cancer Treated With Definitive Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Huihua [Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan (China); Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao, Zhongxing, E-mail: zliao@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liu, Zhensheng [Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Xu, Ting [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Qiming; Liu, Hongliang [Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Komaki, Ritsuko; Gomez, Daniel [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wang, Li-E [Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Wei, Qingyi, E-mail: qwei@mdanderson.org [Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-03-15

    Purpose: The ataxia telangiectasia mutated (ATM) gene mediates detection and repair of DNA damage. We investigated associations between ATM polymorphisms and severe radiation-induced pneumonitis (RP). Methods and Materials: We genotyped 3 potentially functional single nucleotide polymorphisms (SNPs) of ATM (rs1801516 [D1853N/5557G>A], rs189037 [-111G>A] and rs228590) in 362 patients with non-small cell lung cancer (NSCLC), who received definitive (chemo)radiation therapy. The cumulative severe RP probabilities by genotypes were evaluated using the Kaplan-Meier analysis. The associations between severe RP risk and genotypes were assessed by both logistic regression analysis and Cox proportional hazard model with time to event considered. Results: Of 362 patients (72.4% of non-Hispanic whites), 56 (15.5%) experienced grade ≥3 RP. Patients carrying ATM rs189037 AG/GG or rs228590 TT/CT genotypes or rs189037G/rs228590T/rs1801516G (G-T-G) haplotype had a lower risk of severe RP (rs189037: GG/AG vs AA, adjusted hazard ratio [HR] = 0.49, 95% confidence interval [CI], 0.29-0.83, P=.009; rs228590: TT/CT vs CC, HR=0.57, 95% CI, 0.33-0.97, P=.036; haplotype: G-T-G vs A-C-G, HR=0.52, 95% CI, 0.35-0.79, P=.002). Such positive findings remained in non-Hispanic whites. Conclusions: ATM polymorphisms may serve as biomarkers for susceptibility to severe RP in non-Hispanic whites. Large prospective studies are required to confirm our findings.

  4. ATM Polymorphisms Predict Severe Radiation Pneumonitis in Patients With Non-Small Cell Lung Cancer Treated With Definitive Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: The ataxia telangiectasia mutated (ATM) gene mediates detection and repair of DNA damage. We investigated associations between ATM polymorphisms and severe radiation-induced pneumonitis (RP). Methods and Materials: We genotyped 3 potentially functional single nucleotide polymorphisms (SNPs) of ATM (rs1801516 [D1853N/5557G>A], rs189037 [-111G>A] and rs228590) in 362 patients with non-small cell lung cancer (NSCLC), who received definitive (chemo)radiation therapy. The cumulative severe RP probabilities by genotypes were evaluated using the Kaplan-Meier analysis. The associations between severe RP risk and genotypes were assessed by both logistic regression analysis and Cox proportional hazard model with time to event considered. Results: Of 362 patients (72.4% of non-Hispanic whites), 56 (15.5%) experienced grade ≥3 RP. Patients carrying ATM rs189037 AG/GG or rs228590 TT/CT genotypes or rs189037G/rs228590T/rs1801516G (G-T-G) haplotype had a lower risk of severe RP (rs189037: GG/AG vs AA, adjusted hazard ratio [HR] = 0.49, 95% confidence interval [CI], 0.29-0.83, P=.009; rs228590: TT/CT vs CC, HR=0.57, 95% CI, 0.33-0.97, P=.036; haplotype: G-T-G vs A-C-G, HR=0.52, 95% CI, 0.35-0.79, P=.002). Such positive findings remained in non-Hispanic whites. Conclusions: ATM polymorphisms may serve as biomarkers for susceptibility to severe RP in non-Hispanic whites. Large prospective studies are required to confirm our findings

  5. Gene expression profiles and genetic damage in benzo(a)pyrene diol epoxide-exposed TK6 cells

    International Nuclear Information System (INIS)

    Microarray analysis is a powerful tool to identify the biological effects of drugs or chemicals on cellular gene expression. In this study, we compare the relationships between traditional measures of genetic toxicology and mutagen-induced alterations in gene expression profiles. TK6 cells were incubated with 0.01, 0.1, or 1.0 μM ±anti-benzo(a)pyrene-trans-7,8-dihydrodiol-9,10-epoxide (BPDE) for 4 h and then cultured for an additional 20 h. Aliquots of the exposed cells were removed at 4 and 24 h in order to quantify DNA adduct levels by 32P post-labeling and measure cell viability by cloning efficiency and flow cytometry. Gene expression profiles were developed by extracting total RNA from the control and exposed cells at 4 and 24 h, labeling with Cy3 or Cy5 and hybridizing to a human 350 gene array. Mutant frequencies in the Thymidine Kinase and Hypoxanthine Phosphoribosyl Transferase genes were also determined. The 10α-(deoxyguanosin-N2-yl)-7α,8β,9β-trihydroxy-7,8,9,10-tetrahydrobenzo(a) pyrene (dG-N2-BPDE) adduct increased as a function of dose and was the only adduct identified. A dose-related decrease in cell viability was evident at 24 h, but not at 4 h. Cell death occurred by apoptosis. At 4 h, analysis of the gene expression profiles revealed that Glutathione Peroxidase and Gadd45 were consistently upregulated (greater than 1.5-fold and significantly (P<0.001) greater than the control in two experiments) in response to 1.0 μM BPDE exposure. Fifteen genes were consistently down-regulated (less than 0.67-fold and significantly (P<0.001) lower than the control in two experiments) at 4 h in cultures exposed to 1.0 μM BPDE. Genes with altered expression at 4 h included genes important in the progression of the cell-cycle and those that inhibit apoptosis. At 24 h post-exposure, 16 genes, involved in cell-cycle control, detoxification, and apoptosis were consistently upregulated; 10 genes were repressed in cultures exposed to the high dose of BPDE. Real

  6. Transcriptomic Analysis of Cultured Whale Skin Cells Exposed to Hexavalent Chromium [Cr(VI)

    OpenAIRE

    Pabuwal, Vagmita; Boswell, Mikki; Pasquali, Amanda; Wise, Sandra S.; Kumar, Suresh; Shen, Yingjia; Garcia, Tzintzuni; LaCerte, Carolyne; Wise, John Pierce; Warren, Wesley; Walter, Ronald B.

    2013-01-01

    Hexavalent chromium Cr(VI) is known to produce cytotoxic effects in humans and is a highly toxic environmental contaminant. Interestingly, it has been shown that free ranging sperm whales (Phyester macrocephalus) may have exceedingly high levels of Cr in their skin. Also, it has been demonstrated that skin cells from whales appear more resistant to both cytotoxicity and clastogenicity upon Cr exposure compared to human cells. However, the molecular genetic mechanisms employed in whale skin ce...

  7. DNA repair in mammalian cells exposed to combinations of carcinogenic agents

    International Nuclear Information System (INIS)

    Cells defective in one or more aspects of repair are killed and often mutagenized more readily than normal cells by DNA damaging agents, and humans whose cells are deficient in repair are at an increased carcinogenic risk compared to normal individuals. The excision repair of uv induced pyrimidine dimers is a well studied system, but the details of the steps in this repair system are far from being understood in human cells. We know that there are a number of chemicals that mimic uv in that normal human cells repair DNA damage from both these agents and from uv by a long patch excision repair system, and that xeroderma pigmentosum cells defective in repair of uv are also defective in the repair of damage from these chemicals. The chemicals we have investigated are AAAF, 4-NQO, DMBA-epoxide, and ICR-170. We describe experiments, using several techniques, in which DNA excision repair is measured after treatment of various human cell strains with combinations of uv and these agents. If two agents have a common rate limiting step then, at doses high enough to saturate the repair system, one would expect the observed repair after a treatment with a combination of agents to be equal to that from one agent alone. Such is not the case for normal human or excision-deficient XP cells. In the former repair is additive and in the latter repair is usually appreciably less than that observed with either agent alone. Models that attempt to explain these surprising results involve complexes of enzymes and cofactors

  8. Analysis of lysosomal membrane proteins exposed to melanin in HeLa cells

    OpenAIRE

    Bang, Seung Hyuck; Park, Dong Jun; Kim, Yang-Hoon; Min, Jiho

    2016-01-01

    Objectives There have been developed to use targeting ability for antimicrobial, anticancerous, gene therapy and cosmetics through analysis of various membrane proteins isolated from cell organelles. Methods It was examined about the lysosomal membrane protein extracted from lysosome isolated from HeLa cell treated by 100 ppm melanin for 24 hours in order to find associated with targeting ability to melanin using by 2-dimensional electrophoresis. Results The result showed 14 up-regulated (1.5...

  9. Induction of anchorage-independent growth in primary human cells exposed to protons or HZE ions separately or in dual exposures.

    Science.gov (United States)

    Sutherland, B M; Cuomo, N C; Bennett, P V

    2005-10-01

    Travelers on space missions will be exposed to a complex radiation environment that includes protons and heavy charged particles. Since protons are present at much higher levels than are heavy ions, the most likely scenario for cellular radiation exposure will be proton exposure followed by a hit by a heavy ion. Although the effects of individual ion species on human cells are being investigated extensively, little is known about the effects of exposure to both radiation types. One useful measure of mammalian cell damage is induction of the ability to grow in a semi-solid agar medium highly inhibitory to the growth of normal human cells, termed neoplastic transformation. Using primary human cells, we evaluated induction of soft-agar growth and survival of cells exposed to protons only or to heavy charged particles (600 MeV/nucleon silicon) only as well as of cells exposed to protons followed after a 4-day interval by silicon ions. Both ions alone efficiently transformed the human cells to anchorage-independent growth. Initial experiments indicate that the dose responses for neoplastic transformation of cells exposed to protons and then after 4 days to silicon ions appear similar to that of cells exposed to silicon ions alone. PMID:16187755

  10. Interleukin 1 beta initially sensitizes and subsequently protects murine intestinal stem cells exposed to photon radiation

    International Nuclear Information System (INIS)

    Interleukin 1 (IL-1) has been shown to prevent early bone marrow-related death following total-body irradiation, by protecting hematopoietic stem cells and speeding marrow repopulation. This study assesses the effect of IL-1 on the radiation response of the intestinal mucosal stem cell, a nonhematopoietic normal cell relevant to clinical radiation therapy. As observed with bone marrow, administration of human recombinant IL-1 beta (4 micrograms/kg) to C3H/Km mice 20 h prior to total-body irradiation modestly protected duodenal crypt cells. In contrast to bone marrow, IL-1 given 4 or 8 h before radiation sensitized intestinal crypt cells. IL-1 exposure did not substantially alter the slope of the crypt cell survival curve but did affect the shoulder: the X-ray survival curve was offset to the right by 1.01 +/- 0.06 Gy when IL-1 was given 20 h earlier and by 1.28 +/- 0.08 Gy to the left at the 4-h interval. Protection was greatest when IL-1 was administered 20 h before irradiation, but minimal effects persisted as long as 7 days after a single injection. The magnitude of radioprotection at 20 h or of radiosensitization at 4 h increased rapidly as IL-1 dose increased from 0 to 4 micrograms/kg. However, doses ranging from 10 to 100 micrograms/kg produced no further difference in radiation response. Animals treated with saline or IL-1 had similar core temperatures from 4 to 24 h after administration, suggesting that thermal changes were not responsible for either sensitization or protection. Mice irradiated 20 h after IL-1 had significantly greater crypt cell survival than saline-treated irradiated controls at all assay times, which ranged from 54 to 126 h following irradiation. The intervals to maximum crypt depopulation and initiation of repopulation were identical in both saline- and IL-1-treated groups

  11. Cell proliferation of neurons in fetal brain in rat exposed in vitro to β radiation from HTO

    International Nuclear Information System (INIS)

    Flow cytometry, MTT method, cytochrome C reduction, RT-PCR and pulsed field gel electrophoresis (PFGE) were used respectively to determine apoptosis, the inhibition of cell proliferation, the release of superoxide anion (O2-), the expression of p53 gene and DNA double strand break (DSBs) to investigate the insults to neurons in fetal brain in rat exposed in vitro to 0-3.74 x 106 Bq/ml of tritiated water (HTO). Results showed that apoptotic rate, inhibition rate of cell proliferation and expression of p53 mRNA of neurons all increased with the increment of radiation concentration of HTO, in parallel, the extent of DSBs in neurons also aggravated with enlarged dose. But the release quantity of O2- decreased with enlarged dose. All those suggested that HTO β radiation could inhibit the proliferation of neurons via the apoptosis induced by DSBs and p53 gene expression and the decrease of release of O2-. (authors)

  12. IFNγ/IL-10 co-producing cells dominate the CD4 response to malaria in highly exposed children.

    Directory of Open Access Journals (Sweden)

    Prasanna Jagannathan

    2014-01-01

    highly exposed children. These CD4(+ T cells may play important modulatory roles in the development of antimalarial immunity.

  13. Cell proliferation and 3H-proline incorporation in periodontal ligament exposed to mechanical stress

    International Nuclear Information System (INIS)

    In order to study the metabolic processes induced in the periodontal ligament by mechanical influences, a tension spring was implanted in rats between the incisor and the first maxillary molar on the right-hand side, while the left maxilla of these animals as well as non-operated rats served as controls. Under such mechanical stress, there occurred at 3, 10 and 21 days after implantation a significant increase in the 3H-thymidine labelling index, which was demonstrate histoautoradiographically. A change in cell density was not discovered. Therefore, the increase in S-phase fraction as equally recorded in both pressure and tension zones is regarded as an expression of an enhanced cell turnover. Cell renewal in the periodontal ligament can be modified by inflammatory processes within the gingival region. There is a slight enlargement of the periodontal space in the tension zone. Under experimental conditions, no change occurs in the silver grain number per cell after 3H-proline administration. The results indicate that, following the impact of orthodontic forces, the reactivity of periodontal cell proliferation as compared to collagen synthesis is enhanced. (author)

  14. Mutational pattern of TP53 tumor suppressor gene in human lung cells exposed to air pollution PM2.5

    International Nuclear Information System (INIS)

    Environmental exposure to fine airborne particulate matter (PM 2.5) is thought to be responsible for cardiopulmonary diseases, including lung cancer. However, the mechanisms of action potentially involved in PM2.5 toxicity are not yet fully described. Mutations in the TP53 gene are the most common alterations in human solid tumors. TP53 mutational patterns have sometimes been linked to carcinogen exposure. The purpose of this study was to determine the mutations that alter the functionality of this transcription factor in a model of human epithelial lung cells (A549) exposed to the fine particulate fraction (PM2.5) of an atmospheric aerosol sampled under urban and industrial influences. PM2.5 was collected in Dunkerque City by cascade impaction. Its physicochemical characterization revealed the presence of many inorganic and organic compounds, including some that are known for their toxicity. The search for mutations altering the functionality of the P53 protein was performed 72 h after exposure of A549 cells to PM2.5 at its lethal concentration at 50% (LC50, 118.60 μg/mL = 31.63 μg/cm2 ), using the Functional Analysis of Separated Alleles in Yeast (FASAY). Sixteen mutations altering P53 function were detected after A549 cells exposure to the collected PM2.5: eight deletions of one or two nucleotides and eight nucleotide substitutions, mainly transitions A > G and G > A. These mutations are described in the literature as possibly caused by endogenous mechanisms, such as oxidative stress. This kind of alteration can be induced by metal content of the PM2.5, as well as by metabolic activation of the organic compounds coated onto its surface. Involvement of oxidative stress in TP53 mutations was confirmed by the detection of an oxidative DNA adduct, 8-hydroxy-2'-deoxyguanosine (8-OHdG), in A549 cells exposed to the collected PM. (authors)

  15. DJ1 Expression Downregulates in Neuroblastoma Cells (SK-N-MC Chronically Exposed to HIV-1 and Cocaine.

    Directory of Open Access Journals (Sweden)

    Upal eRoy

    2015-07-01

    Full Text Available Background: HIV-associated neurological disorder (HAND has long been recognized as a consequence of Human Immunodeficiency Virus (HIV infection in the brain. The pathology of HAND gets more complicated with the recreational drug use such as cocaine. Recent studies have suggested multiple genetic influences involved in the pathology of addiction and HAND but only a fraction of the entire genetic risk has been investigated so far. In this regard, role of DJ1 protein (a gene linked to autosomal recessive early-onset Parkinson’s disease in regulating dopamine transmission and reactive oxygen species (ROS production in neuronal cells will be worth investigating in HIV-1 and cocaine exposed microenvironment. Being a very abundant protein in the brain, DJ1 could serve as a potential marker for early detection of HIV-1 and/or cocaine related neurological disorder.Methods: In vitro analysis was done to observe the effect of HIV-1 and/or cocaine on DJ1 protein expression in neuroblastoma cells (SK-N-MC. Gene expression and protein analysis of DJ1 was done on the HIV infected and/or cocaine treated SK-N-MC and compared to untreated cells using real time PCR, Western Blot and flow cytometry.Results: Gene expression and protein analysis indicated that there was a significant decrease in DJ1 expression in SK-N-MC chronically exposed to HIV-1 and/or cocaine.Conclusion: This is the first study to establish that DJ1 expression level in the neuronal cells significantly decreased in presence of HIV-1and/or cocaine indicating oxidative stress level of dopamine neurons.

  16. Induction of Poly(ADP-ribose) Polymerase in Mouse Bone Marrow Stromal Cells Exposed to 900 MHz Radiofrequency Fields: Preliminary Observations

    Science.gov (United States)

    He, Qina; Sun, Yulong; Zong, Lin; Tong, Jian; Cao, Yi

    2016-01-01

    Background. Several investigators have reported increased levels of poly(ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme which plays an important role in the repair of damaged DNA, in cells exposed to extremely low dose ionizing radiation which does not cause measurable DNA damage. Objective. To examine whether exposure of the cells to nonionizing radiofrequency fields (RF) is capable of increasing messenger RNA of PARP-1 and its protein levels in mouse bone marrow stromal cells (BMSCs). Methods. BMSCs were exposed to 900 MHz RF at 120 μW/cm2 power intensity for 3 hours/day for 5 days. PARP-1 mRNA and its protein levels were examined at 0, 0.5, 1, 2, 4, 6, 8, and 10 hours after exposure using RT-PCR and Western blot analyses. Sham-exposed (SH) cells and those exposed to ionizing radiation were used as unexposed and positive control cells. Results. BMSCs exposed to RF showed significantly increased expression of PARP-1 mRNA and its protein levels after exposure to RF while such changes were not observed in SH-exposed cells. Conclusion. Nonionizing RF exposure is capable of inducing PARP-1.

  17. Mutant quantity and quality in mammalian cells (AL) exposed to cesium-137 gamma radiation: Effect of caffeine

    International Nuclear Information System (INIS)

    We examined the effect of caffeine (1,3,7-trimethylxanthine) on the quantity and quality of mutations in cultured mammalian AL human-hamster hybrid cells exposed to 137Cs γ radiation. At a dose (1.5 mg/ml for 16 h) that reduced the plating efficiency (PE) by 20%, caffeine was not itself a significant mutagen, but it increased by approximately twofold the slope of the dose-response curve for induction of S1- mutants by 137Cs γ radiation. Molecular analysis of 235 S1- mutants using a series of DNA probes mapped to the human chromosome 11 in the AL hybrid cells revealed that 73 to 85% of the mutations in unexposed cells and in cells treated with caffeine alone, 137Cs γ rays alone or 137Cs γ rays plus caffeine were large deletions involving millions of base pairs of DNA. Most of these deletions were contiguous with the region of the MIC1 gene at 11p13 that encodes the S1 cell surface antigen. In other mutants that had suffered multiple marker loss, the deletions were intermittent along chromosome 11. These open-quotes complexclose quotes mutations were rare for 137Cs γ irradiation (1/63 = 1.5%) but relatively prevalent (23-50%) for other exposure conditions. Thus caffeine appears to alter both the quantity and quality of mutations induced by 137Cs γ irradiation. 62 refs., 3 figs., 3 tabs

  18. Gypenosides Protected the Neural Stem Cells in the Subventricular Zone of Neonatal Rats that Were Prenatally Exposed to Ethanol

    Directory of Open Access Journals (Sweden)

    Lun Dong

    2014-11-01

    Full Text Available Fetal alcohol spectrum disorder (FASD can cause severe mental retardation in children who are prenatally exposed to ethanol. The effects of prenatal and early postnatal ethanol exposure on adult hippocampal neurogenesis have been investigated; however, the effects of prenatal ethanol exposure on the subventricular zone (SVZ have not. Gypenosides (GPs have been reported to have neuroprotective effects in addition to other bioactivities. The effects of GPs on neural stem cells (NSCs in the FASD model are unknown. Here, we test the effect of prenatal ethanol exposure on the neonatal SVZ, and the protection potential of GPs on NSCs in FASD rats. Our results show that prenatal ethanol exposure can suppress the cell proliferation and differentiation of neural stem cells in the neonatal SVZ and that GPs (400 mg/kg/day can significantly increase the cell proliferation and differentiation of neural stem cells inhibited by ethanol. Our data indicate that GPs have neuroprotective effects on the NSCs and can enhance the neurogenesis inhibited by ethanol within the SVZ of neonatal rats. These findings provide new evidence for a potential therapy involving GPs for the treatment of FASD.

  19. Uroporphyrinogen-I-synthetase activity in red blood cells of lead-exposed workers

    Energy Technology Data Exchange (ETDEWEB)

    El-Waseef, A.

    1982-01-01

    Lead-exposed (n . 26) and control (n . 12) subjects were investigated for their blood lead concentration erythrocyte 5-amino-laevulinic acid dehydratase (5-ALAD) and erythrocyte uroporphyrinogen-I-synthetase (URO-I-S) activity; 5-amino-laevulinic acid (5-ALA) and porphobilinogen (PBG) were used as substrates in the synthetase assay. In the lead workers erythrocyte 5-ALA dehydratase was grossly inhibited but with PBG as substrate the synthetase activity was not significantly different from the control group. With 5-ALA as substrate the synthetase assay showed marked inhibition. Addition of zinc (0.1 mmol/l) and dithiotheritol (0.5 mmol/l) brought the activities of both the dehydratase and synthetase (using 5-ALA as substrate) back into the ranges seen in the control group. With porphobilinogen as substrate higher concentrations of zinc caused inhibition of the synthetase, whilst reduction of added zinc to 0.01 mmol/l resulted in stimulation of the synthetase. A good correlation (r . 0.87) was obtained in synthetase assay when PBG and 5-aminolaevulinate (with added zinc and dithiothreitol) were used as substrates. With these additions 5-ALA may be used as a substrate in the URO-I-S assay in the investigation of latent cases of acute intermittent porphyria.

  20. Bone-Marrow Stem-Cell Survival in the Non-Uniformly Exposed Mammal

    International Nuclear Information System (INIS)

    For comparison of the effectiveness of non-uniform versus uniform irradiations in causing haematological death in mammals, a model of the irradiated haemopoietic system has been proposed. The essential features of this model are: (1) that different parts of the haemopoietic system have numbers of stem cells which are proportioned to the amounts of active marrow in those parts as measured by 59Fe uptake, (2) that stem cells in the different parts are subject to the, same dose-survival relationship, and (3) that survival of the animal depends on survival of a critical fraction of the total number of stem cells independent of their distribution among the parts of the total marrow mass. To apply this model one needs to know: (a) the relative 59Fe uptakes of the different parts of the haemopoietic system, (b) the doses delivered to those parts by each of the exposures to be compared, and (c) the dose-survival curve applicable to the stem cells. From these one can calculate the fraction of stem cells surviving each exposure. In a preliminary communication the applicability of the model was investigated using data obtained entirely from the literature. Additional data, particularly on bone-marrow distribution, have since been obtained and are included here. The primary object of the present paper is to test further the validity of the above 'stem-cell survival model'. Data on bilateral (essentially uniform) versus unilateral and non-uniform rotational exposures in mammals are examined with respect to the surviving fraction of stem cells at the LD50/30 day dose level. Although an adequate test is not possible at present for lack of a full set of data in any one species, a partial test indicates compatibility with data for dogs and rats. Other possible mortality determinants such as doses or exposures at entrance, midline or exit, or the gram-rads or average dose to the marrow, appear to be less useful than the critical stem-cell survival fraction

  1. Heterogeneity in c-jun gene expression in normal and malignant cells exposed to either ionizing radiation or hydrogen peroxide

    International Nuclear Information System (INIS)

    We investigated the role of reactive oxygen intermediates and protein kinase C (PKC) in induction of c-jun gene expression in human ML-2 leukemic cells and normal DET-551 fibroblasts by comparing the effects of either ionizing radiation or H2O2 exposure in the presence or absence of appropriate inhibitors. In these cell types, the radiation and H2O2-mediated increase in c-jun mRNA levels could be prevented by pretreatment of the cells with N-acetylcysteine, an antioxidant, or H7, an inhibitor of PKC and cAMP-dependent protein kinase (PKA), but not by HA1004, an inhibitor of PKA. These results suggest a role for PKC and reactive oxygen intermediates in the induction of c-jun gene expression in both normal and tumor cells. We also investigated potential differences in radiation- or H2O2-induced c-jun gene expression in normal and tumor cells by examining steady-state c-jun mRNA levels in a number of human fibroblast, leukemia, melanoma, sarcoma, and carcinoma cell types. We observed heterogeneity in the steady-state level of c-jun mRNA in both the untreated normal and tumor cells and in such cells exposed to ionizing radiation or to H2O2. Exposure to radiation or to hydrogen peroxide produced a varied response which ranged from little or no induction to a more than two orders of magnitude increase in the steady-state level of the c-jun mRNA

  2. Effect of recombinant IL-10 on cultured fetal rat alveolar type II cells exposed to 65%-hyperoxia

    Directory of Open Access Journals (Sweden)

    Lee Hyeon-Soo

    2011-05-01

    Full Text Available Abstract Background Hyperoxia plays an important role in the genesis of lung injury in preterm infants. Although alveolar type II cells are the main target of hyperoxic lung injury, the exact mechanisms whereby hyperoxia on fetal alveolar type II cells contributes to the genesis of lung injury are not fully defined, and there have been no specific measures for protection of fetal alveolar type II cells. Objective The aim of this study was to investigate (a cell death response and inflammatory response in fetal alveolar type II cells in the transitional period from canalicular to saccular stages during 65%-hyperoxia and (b whether the injurious stimulus is promoted by creating an imbalance between pro- and anti-inflammatory cytokines and (c whether treatment with an anti-inflammatory cytokine may be effective for protection of fetal alveolar type II cells from injury secondary to 65%-hyperoxia. Methods Fetal alveolar type II cells were isolated on embryonic day 19 and exposed to 65%-oxygen for 24 h and 36 h. Cells in room air were used as controls. Cellular necrosis was assessed by lactate dehydrogenase-release and flow cytometry, and apoptosis was analyzed by TUNEL assay and flow cytometry, and cell proliferation was studied by BrdU incorporation. Release of cytokines including VEGF was analyzed by ELISA, and their gene expressions were investigated by qRT-PCR. Results 65%-hyperoxia increased cellular necrosis, whereas it decreased cell proliferation in a time-dependent manner compared to controls. 65%-hyperoxia stimulated IL-8-release in a time-dependent fashion, whereas the anti-inflammatory cytokine, IL-10, showed an opposite response. 65%-hyperoxia induced a significant decrease of VEGF-release compared to controls, and similar findings were observed on IL-8/IL-10/VEGF genes expression. Preincubation of recombinant IL-10 prior to 65%-hyperoxia decreased cellular necrosis and IL-8-release, and increased VEGF-release and cell proliferation

  3. Global gene expression changes in human urothelial cells exposed to low-level monomethylarsonous acid

    Czech Academy of Sciences Publication Activity Database

    Medeiros, M.; Zheng, X.; Novák, Petr; Wnek, S.M.; Chyan, V.; Escudero-Lourdes, C.; Gandolfi, A.J.

    2012-01-01

    Roč. 291, 1-3 (2012), s. 102-112. ISSN 0300-483X Institutional research plan: CEZ:AV0Z50510513 Institutional support: RVO:60077344 Keywords : HUMAN BLADDER CELLS * METHYLATED TRIVALENT ARSENICALS * MALIGNANT-TRANSFORMATION0300 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.017, year: 2012

  4. Reduced growth rate of tumors from melanoma cells exposed to focused shock waves

    Czech Academy of Sciences Publication Activity Database

    Šunka, Pavel; Stelmashuk, Vitaliy; Beneš, J.; Poučková, P.

    Washington D.C., USA: -, 2006 - (Curry, R.). s. 184 [International Power Modulator Conference 2006. 14.5.2006-18.5.2006, International Power Modulator Conference 2006] R&D Projects: GA ČR(CZ) GA202/05/0685 Institutional research plan: CEZ:AV0Z20430508 Keywords : Focused shock waves * tumor * melanoma cells * cavitations Subject RIV: BI - Acoustics

  5. Nanomimics of host cell membranes block invasion and expose invasive malaria parasites.

    Science.gov (United States)

    Najer, Adrian; Wu, Dalin; Bieri, Andrej; Brand, Françoise; Palivan, Cornelia G; Beck, Hans-Peter; Meier, Wolfgang

    2014-12-23

    The fight against most infectious diseases, including malaria, is often hampered by the emergence of drug resistance and lack or limited efficacies of vaccines. Therefore, new drugs, vaccines, or other strategies to control these diseases are needed. Here, we present an innovative nanotechnological strategy in which the nanostructure itself represents the active substance with no necessity to release compounds to attain therapeutic effect and which might act in a drug- and vaccine-like dual function. Invasion of Plasmodium falciparum parasites into red blood cells was selected as a biological model for the initial validation of this approach. Stable nanomimics-polymersomes presenting receptors required for parasite attachment to host cells-were designed to efficiently interrupt the life cycle of the parasite by inhibiting invasion. A simple way to build nanomimics without postformation modifications was established. First, a block copolymer of the receptor with a hydrophobic polymer was synthesized and then mixed with a polymersome-forming block copolymer. The resulting nanomimics bound parasite-derived ligands involved in the initial attachment to host cells and they efficiently blocked reinvasion of malaria parasites after their egress from host cells in vitro. They exhibited efficacies of more than 2 orders of magnitude higher than the soluble form of the receptor, which can be explained by multivalent interactions of several receptors on one nanomimic with multiple ligands on the infective parasite. In the future, our strategy might offer interesting treatment options for severe malaria or a way to modulate the immune response. PMID:25435059

  6. Measurement of oxidative damage to DNA in nanomaterial exposed cells and animals

    DEFF Research Database (Denmark)

    Møller, Peter; Jensen, Ditte Marie; Christophersen, Daniel Vest;

    2015-01-01

    -reactivity with other molecules in cells. This review provides an overview of efforts to reliably detect oxidatively damaged DNA and a critical assessment of the published studies on DNA damage levels. Animal studies with high baseline levels of oxidatively damaged DNA are more likely to show positive associations...

  7. Enhancement of cetuximab on radiosensitivity of colorectal cancer cells exposed to 125I seeds

    International Nuclear Information System (INIS)

    Objective: To investigate the effect of cetuximab (C225) on the radiosensitivity of colorectal cancer cells CL187 and underlying mechanism. Methods: Cell survival was detected by colony forming assay. The levels of apoptosis and cell cycle distribution were determined by flow cytometer. The mitotic ratio was measured by Wright's-Giemsa mixed coloring method. The protein levels of Bax and Bcl2 were detected by Western blot. Results: The sensitizing enhancement ratio of C225 was approximately 1.4. C225 treatment and 125I seed radiation induced G1 cell cycle arrest individually. C225 increased the radiation-induced apoptosis (t =6.6, P<0.05) and cellular Bax/Bcl-2 ratio (t =9.4, P<0.05), but did not increase radiation-induced G1 arrest. In addition, there was no difference in mitotic index among different groups. Conclusions: C225 sensitizes CL187 to 125I seed irradiation,which might be related with increase of radiation-induced apoptosis. (authors)

  8. Photobiomodulation Protects and Promotes Differentiation of C2C12 Myoblast Cells Exposed to Snake Venom

    Science.gov (United States)

    da Silva, Aline; Vieira, Rodolfo Paula; Mesquita-Ferrari, Raquel Agnelli; Cogo, José Carlos; Zamuner, Stella Regina

    2016-01-01

    Background Snakebites is a neglected disease and in Brazil is considered a serious health problem, with the majority of the snakebites caused by the genus Bothrops. Antivenom therapy and other first-aid treatments do not reverse local myonecrose which is the main sequel caused by the envenomation. Several studies have shown the effectiveness of low level laser (LLL) therapy in reducing local myonecrosis induced by Bothropic venoms, however the mechanism involved in this effect is unknown. In this in vitro study, we aimed to analyze the effect of LLL irradiation against cytotoxicity induced by Bothrops jararacussu venom on myoblast C2C12 cells. Methodology C2C12 were utilized as a model target and were incubated with B. jararacussu venom (12.5 μg/mL) and immediately irradiated with LLL at wavelength of red 685 nm or infrared 830 nm with energy density of 2.0, 4.6 and 7.0 J/cm2. Effects of LLL on cellular responses of venom-induced cytotoxicity were examined, including cell viability, measurement of cell damage and intra and extracellular ATP levels, expression of myogenic regulatory factors, as well as cellular differentiation. Results In non-irradiated cells, the venom caused a decrease in cell viability and a massive release of LDH and CK levels indicating myonecrosis. Infrared and red laser at all energy densities were able to considerably decrease venom-induced cytotoxicity. Laser irradiation induced myoblasts to differentiate into myotubes and this effect was accompanied by up regulation of MyoD and specially myogenin. Moreover, LLL was able to reduce the extracellular while increased the intracellular ATP content after venom exposure. In addition, no difference in the intensity of cytotoxicity was shown by non-irradiated and irradiated venom. Conclusion LLL irradiation caused a protective effect on C2C12 cells against the cytotoxicity caused by B. jararacussu venom and promotes differentiation of these cells by up regulation of myogenic factors. A modulatory

  9. Gene expression profile of human lung epithelial cells chronically exposed to single-walled carbon nanotubes

    Science.gov (United States)

    Chen, Dongquan; Stueckle, Todd A.; Luanpitpong, Sudjit; Rojanasakul, Yon; Lu, Yongju; Wang, Liying

    2015-01-01

    A rapid increase in utility of engineered nanomaterials, including carbon nanotubes (CNTs), has raised a concern over their safety. Based on recent evidence from animal studies, pulmonary exposure of CNTs may lead to nanoparticle accumulation in the deep lung without effective clearance which could interact with local lung cells for a long period of time. Physicochemical similarities of CNTs to asbestos fibers may contribute to their asbestos-like carcinogenic potential after long-term exposure, which has not been well addressed. More studies are needed to identify and predict the carcinogenic potential and mechanisms for promoting their safe use. Our previous study reported a long-term in vitro exposure model for CNT carcinogenicity and showed that 6-month sub-chronic exposure of single-walled carbon nanotubes (SWCNT) causes malignant transformation of human lung epithelial cells. In addition, the transformed cells induced tumor formation in mice and exhibited an apoptosis resistant phenotype, a key characteristic of cancer cells. Although the potential role of p53 in the transformation process was identified, the underlying mechanisms of oncogenesis remain largely undefined. Here, we further examined the gene expression profile by using genome microarrays to profile molecular mechanisms of SWCNT oncogenesis. Based on differentially expressed genes, possible mechanisms of SWCNT-associated apoptosis resistance and oncogenesis were identified, which included activation of pAkt/p53/Bcl-2 signaling axis, increased gene expression of Ras family for cell cycle control, Dsh-mediated Notch 1, and downregulation of apoptotic genes BAX and Noxa. Activated immune responses were among the major changes of biological function. Our findings shed light on potential molecular mechanisms and signaling pathways involved in SWCNT oncogenic potential.

  10. Biocompatibility and degradation of gold-covered magneto-elastic biosensors exposed to cell culture.

    Science.gov (United States)

    Menti, C; Beltrami, M; Possan, A L; Martins, S T; Henriques, J A P; Santos, A D; Missell, F P; Roesch-Ely, M

    2016-07-01

    Magneto-elastic materials (ME) have important advantages when applied as biosensors due to the possibility of wireless monitoring. Commercial Metglas 2826MB3™ (FeNiMoB) is widely used, however sensor stabilization is an important factor for biosensor performance. This study compared the effects of biocompatibility and degradation of the Metglas 2826MB3™ alloy, covered or not with a gold layer, when in contact with cell culture medium. Strips of amorphous Metglas 2826MB3™ were cut and coated with thin layers of Cr and Au, as verified by Rutherford Backscattering Spectroscopy (RBS). Using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), the presence of metals in the culture medium was quantitatively determined for up to seven days after alloy exposure. Biocompatibility of fibroblast Chinese Hamster Ovary (CHO) cultures was tested and cytotoxicity parameters were investigated by indirect means of reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) at 1, 2 and 7 days. Cell death was further evaluated through in situ analysis using Acridine Orange/Ethidium Bromide (AO/EB) staining and images were processed with ImageJ software. Ions from Metglas(®) 2826MB3™ induced a degradation process in living organisms. The cytotoxicity assay showed a decrease in the percentage of live cells compared to control for the ME strip not coated with gold. AO/EB in situ staining revealed that most of the cells grown on top of the gold-covered sensor presented a normal morphology (85.46%). Covering ME sensors with a gold coating improved their effectiveness by generating protection of the transducer by reducing the release of ions and promoting a significant cell survival. PMID:26998872

  11. Reversible alterations in epithelial cell turnover in digestive gland of winkles (Littorina littorea) exposed to cadmium and their implications for biomarker measurements

    Energy Technology Data Exchange (ETDEWEB)

    Zaldibar, B. [Cell Biology and Histology Laboratory, Zoology and Animal Cell Biology Department, School of Science and Technology, University of the Basque Country, PO Box 644, E-48080 Bilbo, Basque Country (Spain); Cancio, I. [Cell Biology and Histology Laboratory, Zoology and Animal Cell Biology Department, School of Science and Technology, University of the Basque Country, PO Box 644, E-48080 Bilbo, Basque Country (Spain); Marigomez, I. [Cell Biology and Histology Laboratory, Zoology and Animal Cell Biology Department, School of Science and Technology, University of the Basque Country, PO Box 644, E-48080 Bilbo, Basque Country (Spain)]. E-mail: ionan.marigomez@ehu.es

    2007-02-28

    In marine molluscs, the epithelium of the digestive gland is composed of two cell types, namely, digestive and basophilic cells. Under normal physiological conditions digestive cells outnumber basophilic cells, but under different stress situations the composition of the epithelium changes, basophilic cells apparently replace digestive cell. Winkles, Littorina littorea, were exposed to 1.25 mg/l Cd for 20 days to provoke cell type replacement. Then, animals were depurated in clean seawater for 10 days to determine whether cell type replacement was reversible. Digestive glands were fixed in Carnoy and paraffin embedded for histological analysis. The volume densities of basophilic cells (Vv{sub BAS}) and digestive cells (Vv{sub DIG}) were calculated by stereology on hematoxylin-eosin stained sections. Vv{sub BAS} increased and Vv{sub DIG} decreased in Cd-exposed animals. After estimation of cell size and absolute cell numbers, these changes were attributed to digestive cell loss and concomitant basophilic cell hypertrophy but not to increased numbers of basophilic cells. Cell type composition and cell size almost fully returned to normal values after 10-day depuration. Accordingly, PCNA immunohistochemistry demonstrated that proliferating digestive cells were more abundant in winkles exposed to Cd and after 10-day depuration than in control specimens, suggesting that net digestive cell loss was accompanied by increased digestive cell proliferation. Thus, Cd-exposure seems to provoke an enhanced digestive cell turnover in order to cope with Cd detoxification. Intralysosomal accumulation of metals (autometallographied black silver deposits; BSD) was used as a biomarker of exposure to Cd and lysosomal structural changes as an effect biomarker to see whether cell type composition might have any effect on these endpoints. BSD formed around Cd ions, in digestive cell lysosomes of Cd-exposed winkles whereas basophilic cells appeared devoid of them. After depuration, BSD

  12. Somatic cell chromosome changes in a population exposed to low levels of ionizing radiation

    International Nuclear Information System (INIS)

    The analysis of chromosomes from the cells of 897 plutonium workers is reported. Within three years, the number of controls alone analyzed for this study approximated the largest plutonium cytogenetic studies today including workers plus controls (81 compared to 84 in a 1979 French study and 94 in a 1982 British report). The number of subjects analyzed in the first three years were: new employees - 245; new employees assigned to plutonium work areas - 7; workers with less than 3% of maximum permissible systemic burden (MPSB) - 35; workers with less than 50% MPSB - 274; workers with greater than 50% of MPSB - 65; follow-up familial congenital cytogenetics at worker request (through Medical) - 6; polymorphic/variant chromosome constitutions - 242; re-sampling of workers with elevated aberration yields - 26; cell sample study - 28; sister-chromatid-exchange (SCE) study - 23; beryllium workers at Rocky Flats - 10; Hanford worker analyses - 5). 20 refs., 3 figs., 5 tabs

  13. Multiwalled carbon nanotubes enter broccoli cells enhancing growth and water uptake of plants exposed to salinity

    OpenAIRE

    Martínez-Ballesta, Mª Carmen; Zapata, Lavinia; Chalbi, Najla; Carvajal, Micaela

    2016-01-01

    Background Carbon nanotubes have been shown to improve the germination and growth of some plant species, extending the applicability of the emerging nano-biotechnology field to crop science. Results In this work, exploitation of commercial multiwalled carbon nanotubes (MWCNTs) in control and 100 mM NaCl-treated broccoli was performed. Transmission electron microscopy demonstrated that MWCNTs can enter the cells in adult plants with higher accumulation under salt stress. Positive effect of MWC...

  14. Genotoxic and non-genotoxic effects in rat liver epithelial cells exposed to carcinogenic PAHs

    Czech Academy of Sciences Publication Activity Database

    Topinka, Jan; Sevastyanova, Oksana; Marvanová, S.; Vondráček, Jan; Nováková, Zuzana; Milcová, Alena; Krčmář, P.; Pěnčíková, K.; Machala, M.

    Basel, 2007. s. 157. [European Environmental Mutagen Society, 37th Annual Meeting - 2007. 09.09.2007-13.09.2007, Basel] R&D Projects: GA AV ČR(CZ) KJB6004407 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702; CEZ:AV0Z50390512; CEZ:AV0Z50390703 Keywords : DNA adducts * cell proliferation * apoptosis Subject RIV: BO - Biophysics

  15. Regulation of SUMO2 Target Proteins by the Proteasome in Human Cells Exposed to Replication Stress

    DEFF Research Database (Denmark)

    Bursomanno, Sara; McGouran, Joanna F; Kessler, Benedikt M;

    2015-01-01

    In human cells, SUMO2 is predominantly conjugated to target proteins in response to cellular stress. Previous studies suggested that proteins conjugated to SUMO2, but not to SUMO1, could be regulated by the ubiquitin-mediated proteasome system. Hence, we set out to understand the role of the...... genome instability, which is suggested to drive tumorigenesis and possibly aging, our data will facilitate future functional studies in the fields of DNA metabolism and cancer biology....

  16. Extracellular signal-regulated kinases 1 and 2 activation in endothelial cells exposed to cyclic strain

    Science.gov (United States)

    Ikeda, M.; Takei, T.; Mills, I.; Kito, H.; Sumpio, B. E.

    1999-01-01

    The aim of this study was to determine whether extracellular signal-regulated kinases 1/2 (ERK1/ERK2) are activated and might play a role in enhanced proliferation and morphological change induced by strain. Bovine aortic endothelial cells (BAEC) were subjected to an average of 6 or 10% strain at a rate of 60 cycles/min for up to 4 h. Cyclic strain caused strain- and time-dependent phosphorylation and activation of ERK1/ERK2. Peak phosphorylation and activation of ERK1/ERK2 induced by 10% strain were at 10 min. A specific ERK1/ERK2 kinase inhibitor, PD-98059, inhibited phosphorylation and activation of ERK1/ERK2 but did not inhibit the increased cell proliferation and cell alignment induced by strain. Treatment of BAEC with 2,5-di-tert-butyl-1, 4-benzohydroquinone, to deplete inositol trisphosphate-sensitive calcium storage, and gadolinium chloride, a Ca2+ channel blocker, did not inhibit the activation of ERK1/ERK2. Strain-induced ERK1/ERK2 activation was partly inhibited by the protein kinase C inhibitor calphostin C and completely inhibited by the tyrosine kinase inhibitor genistein. These data suggest that 1) ERK1/ERK2 are not critically involved in the strain-induced cell proliferation and orientation, 2) strain-dependent activation of ERK1/ERK2 is independent of intracellular and extracellular calcium mobilization, and 3) protein kinase C activation and tyrosine kinase regulate strain-induced activation of ERK1/ERK2.

  17. Reduced growth rate of tumors from melanoma B16 cells exposed to focused shock waves

    Czech Academy of Sciences Publication Activity Database

    Šunka, Pavel; Stelmashuk, Vitaliy; Beneš, J.; Poučková, P.

    Washington D.C: IEEE, 2007 - (Umstattd, R.), s. 494-497. (IEEE Conference proceedings). ISBN 978-1-4244-0018-8. [IEEE International Power Modulator Conference/2006./. Washington D.C. (US), 15.05.2006-19.05.2006] R&D Projects: GA ČR GA202/05/0685 Institutional research plan: CEZ:AV0Z20430508 Keywords : Shock waves * cavitaions * melanoma cells * reduced growthrate Subject RIV: BL - Plasma and Gas Discharge Physics

  18. Reduced growth rate of tumors from melanoma B16 cells exposed to focused shock waves

    Czech Academy of Sciences Publication Activity Database

    Šunka, Pavel; Stelmashuk, Vitaliy; Beneš, J.; Poučková, P.

    Piscataway: IEEE, 2007 - (Umstattd, R.), s. 494-497. (IEEE Catalog Number: 06CH37746). ISBN 978-1-4244-0018-8. ISSN 1930-885X. [2006 IEEE International Power Modulator Conference. Washington, DC (US), 15.05.2006-19.05.2006] R&D Projects: GA ČR GA202/05/0685 Institutional research plan: CEZ:AV0Z20430508 Keywords : Shock waves * cavitations * melanoma cells * tumor growth rate Subject RIV: BL - Plasma and Gas Discharge Physics

  19. CYTOKINESIS-BLOCK MICRONUCLEUS ASSAY IN HUMAN GLIOMA CELLS EXPOSED TO RADIATION

    Directory of Open Access Journals (Sweden)

    Jerzy Slowinski

    2011-05-01

    Full Text Available Biological tests are efficient in reflecting the biological influences of several types of generally harmful exposures. The micronucleus assay is widely used in genotoxicity studies or studies on genomic damage in general. We present methodological aspects of cytokinesis-block micronucleus assay performed in human gliomas irradiated in vitro. Eight human glioblastoma cell lines obtained from DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Germany were gamma-irradiated (60Co over a dose range of 0-10 Gy. Cytokinesis-block micronucleus assay was performed to quantitate cytogenetic damage. The cells were fixed directly on dishes, stained with fluorochrome DAPI and evaluated under fluorescent and phase contrast microscope. The micronucleus frequency was expressed as a micronuclei (MN per binucleated cell (BNC ratio, calculated after scoring at least 100 BNC per dish. The frequency of spontaneous MN ranged from 0.17 to 0.613 (mean: 0.29 ± 0.14. After irradiation increase of MN frequency in the range of 0.312 - 2.241 (mean: 0.98 ± 0.68 was found at 10 Gy. Gliomas are extremely heterogenous in regard to cytogenetic effects of irradiation, as shown in this study by cytokinesis-block micronucleus assay. This test is easily performed on irradiated glioma cell lines and can assist in determining their radiosensitivity. However, in order to obtain reliable and reproducible results, precise criteria for MN scoring must be strictly followed. Simultaneous use of fluorescent and phase contrast equipment improves imaging of morphological details and can further optimize MN scoring.

  20. Protective Pleiotropic Effect of Flavonoids on NAD + Levels in Endothelial Cells Exposed to High Glucose

    OpenAIRE

    Boesten, Daniëlle M. P. H. J.; von Ungern-Sternberg, Saskia N. I.; den Hartog, Gertjan J. M.; Aalt Bast

    2015-01-01

    NAD+ is important for oxidative metabolism by serving as an electron transporter. Hyperglycemia decreases NAD+ levels by activation of the polyol pathway and by overactivation of poly(ADP-ribose)-polymerase (PARP). We examined the protective role of three structurally related flavonoids (rutin, quercetin, and flavone) during high glucose conditions in an in vitro model using human umbilical vein endothelial cells (HUVECs). Additionally we assessed the ability of these flavonoids to inhibit al...

  1. Dynamics of glutathione-S-transferases in Mytilus galloprovincialis exposed to toxic Microcystis aeruginosa cells, extracts and pure toxins.

    Science.gov (United States)

    Vasconcelos, V M; Wiegand, C; Pflugmacher, S

    2007-11-01

    Molluscs and especially bivalves are able to accumulate dinoflagelates, diatoms and cyanobacteria toxins, and, being vectors for these toxins, transfer them along food chains. The data obtained from laboratory experiments showed that bivalve molluscs are resistant to cyanobacteria toxins. In this work, we wanted to test if Mytilus galloprovincialis organs react to microcystins and other cyanobacteria compounds by inducing or decreasing its GST activity. Acclimated mussels M. galloprovincialis were exposed to the toxic Microcystis aeruginosa M13 strain. Exposure of mussels to toxins was done in three ways: living Microcystis cells, crude Microcystis extracts and pure toxins. The measurement of soluble and microsomal GST activity in the different mussel organs was done by using the substrates 1-chloro-2,4-dinitrobenzene (CDNB) and 2,4-dichloro-1-nitrobenzene (DCNB). Analysis of the GST activity of the control mussels using CDNB as a substrate showed that cytosolic activity is much more significant than microsomal. Intact M. aeruginosa cells did not induce any significant response from the mussels, showing that these animals are quite resistant to the cyanobacteria if they are intact. On the other hand, cell extracts caused an important effect in the gut, in the gills and in the labial palps, although in different ways. There was an increase in GST activity in the gut and gills of mussels exposed to Microcystis extracts, showing a response of this detoxication pathway, but in the labial palps a severe reduction in GST activity occurred. Pure MC LR+YR induced an increase in GST activity in all organs but the labial palps. The results showed that other substances apart from microcystins may cause stress to mussels and affect detoxication enzymes such as GST. PMID:17675203

  2. Photocatalytic Oxidation of Triiodide in UVA-Exposed Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Matthew Carnie

    2012-01-01

    Full Text Available UVA irradiation of glass mounted dye-sensitized solar cells without UV filtration causes failure within 400 hours of light exposure. The failure mode is shown to relate to consumption of I3−, which is directly related to TiO2 photo-catalysis. The onset of failure is easily determined from electrochemical impedance data where the recombination resistance of the TiO2/electrolyte back reaction drops markedly prior to the onset of degradation. At the point of complete cell failure this impedance value then dramatically increases as there is no longer an interfacial reaction possible between the TiO2 and the I3− depleted electrolyte. Device failure is most rapid for cells under electrical load indicating that the degradation of the electrolyte is related to photogenerated hole production by excitation of the TiO2. Once depleted by UV exposure, the I3− can be regenerated by simple application of a reverse bias which can restore severely UV degraded devices to near original working conditions.

  3. MicroRNA-1228(*) inhibit apoptosis in A549 cells exposed to fine particulate matter.

    Science.gov (United States)

    Li, Xiaobo; Ding, Zhen; Zhang, Chengcheng; Zhang, Xin; Meng, Qingtao; Wu, Shenshen; Wang, Shizhi; Yin, Lihong; Pu, Yuepu; Chen, Rui

    2016-05-01

    Studies have reported associations between fine particulate matter (PM2.5) and respiratory disorders; however, the underlying mechanism is not completely clear owing to the complex components of PM2.5. microRNAs (miRNAs) demonstrate tremendous regulation to target genes, which are sensitive to exogenous stimulation, and facilitate the integrative understood of biological responses. Here, significantly modulated miRNA were profiled by miRNA microarray, coupled with bioinformatic analysis; the potential biological function of modulated miRNA were predicted and subsequently validated by cell-based assays. Downregulation of miR-1228-5p (miR-1228(*)) expression in human A549 cells were associated with PM2.5-induced cellular apoptosis through a mitochondria-dependent pathway. Further, overexpression of miR-1228(*) rescued the cellular damages induced by PM2.5. Thus, our results demonstrate that PM2.5-induced A549 apoptosis is initiated by mitochondrial dysfunction and miR-1228(*) could protect A549 cells against apoptosis. The involved pathways and target genes might be used for future mechanistic studies. PMID:26867688

  4. Measurement of chromosomal breakage in cultured cells by the micronucleus technique

    International Nuclear Information System (INIS)

    The results of a series of experiments in which micronuclei were used to measure the extent of chromosomal damage by ionizing radiation are summarized. The data show that in most situations micronuclei accurately reflect chromosomal breakage and that they may be used for rapid and simple estimates of aberration frequency. The results of some studies on trisomy-21, Fanconi's anaemia, Bloom's syndrome and ataxia telangiectasia are included; the advantages and disadvantages of the technique are discussed. (author)

  5. Nuclear survivin and its relationship to DNA damage repair genes in non-small cell lung cancer investigated using tissue array.

    Directory of Open Access Journals (Sweden)

    Songliu Hu

    Full Text Available PURPOSE: To investigate the predictive role and association of nuclear survivin and the DNA double-strand breaks repair genes in non-small cell lung cancer (NSCLC: DNA-dependent protein kinase catalytic subunit (DNA-PKcs, Ku heterodimeric regulatory complex 70-KD subunit (Ku70 and ataxia-telangiectasia mutated (ATM. METHODS: The protein expression of nuclear survivin, DNA-PKcs, Ku70 and ATM were investigated using immunohistochemistry in tumors from 256 patients with surgically resected NSCLC. Furthermore, we analyzed the correlation between the expression of nuclear survivin, DNA-PKcs, Ku70 and ATM. Univariate and multivariate analyses were performed to determine the prognostic factors that inuenced the overall survival and disease-free survival of NSCLC. RESULTS: The expression of nuclear survivin, DNA-PKcs, Ku70 and ATM was significantly higher in tumor tissues than in normal tissues. By dichotomizing the specimens as expressing low or high levels of nuclear survivin, nuclear survivin correlated significantly with the pathologic stage (P = 0.009 and lymph node status (P = 0.004. The nuclear survivin levels were an independent prognostic factor for both the overall survival and the disease-free survival in univariate and multivariate analyses. Patients with low Ku70 and DNA-PKcs expression had a greater benefit from radiotherapy than patients with high expression of Ku70 (P = 0.012 and DNA-PKcs (P = 0.02. Nuclear survivin expression positively correlated with DNA-PKcs (P<0.001 and Ku70 expression (P<0.001. CONCLUSIONS: Nuclear survivin may be a prognostic factor for overall survival in patients with resected stage I-IIIA NSCLC. DNA-PKcs and Ku70 could predict the effect of radiotherapy in patients with NSCLC. Nuclear survivin may also stimulates DNA double-strand breaks repair by its interaction with DNA-PKcs and Ku70.

  6. p38 MAPK-Mediated Bmi-1 down-regulation and defective proliferation in ATM-deficient neural stem cells can be restored by Akt activation.

    Directory of Open Access Journals (Sweden)

    Jeesun Kim

    Full Text Available A-T (ataxia telangiectasia is a genetic disease caused by a mutation in the Atm (A-T mutated gene that leads to neurodegeneration. Despite an increase in the numbers of studies in this area in recent years, the mechanisms underlying neurodegeneration in human A-T are still poorly understood. Previous studies demonstrated that neural stem cells (NSCs isolated from the subventricular zone (SVZ of Atm(-/- mouse brains show defective self-renewal and proliferation, which is accompanied by activation of chronic p38 mitogen-activated protein kinase (MAPK and a lower level of the polycomb protein Bmi-1. However, the mechanism underlying Bmi-1 down-regulation and its relevance to defective proliferation in Atm(-/- NSCs remained unclear. Here, we show that over-expression of Bmi-1 increases self-renewal and proliferation of Atm(-/- NSCs to normal, indicating that defective proliferation in Atm(-/- NSCs is a consequence of down-regulation of Bmi-1. We also demonstrate that epidermal growth factor (EGF-induced Akt phosphorylation renders Bmi-1 resistant to the proteasomal degradation, leading to its stabilization and accumulation in the nucleus. However, inhibition of the Akt-dependent Bmi-1 stabilizing process by p38 MAPK signaling reduces the levels of Bmi-1. Treatment of the Atm(-/- NSCs with a specific p38 MAPK inhibitor SB203580 extended Bmi-1 posttranscriptional turnover and H2A ubiquitination in Atm(-/- NSCs. Our observations demonstrate the molecular basis underlying the impairment of self-renewal and proliferation in Atm(-/- NSCs through the p38 MAPK-Akt-Bmi-1-p21 signaling pathway.

  7. Matrix-degrading and pro-inflammatory changes in human vascular endothelial cells exposed to cigarette smoke condensate.

    Science.gov (United States)

    Nordskog, Brian K; Blixt, Allison D; Morgan, Walter T; Fields, Wanda R; Hellmann, Gary M

    2003-01-01

    Cigarette smoking has been associated with an increase in the severity and prevalence of atherosclerosis in the abdominal aorta. To begin our investigation of this finding, we used an integrated approach combining gene expression profiling, protein analysis, cytokine measurements, and cytotoxicity determinations to examine molecular responses of cultured human aortic and coronary endothelial cells exposed to cigarette smoke condensate (CSC) and nicotine. Exposure of endothelial cells to CSC (30 and 60 microg/mL TPM) for 24 h resulted in minimal cytotoxicity, and the upregulation of genes involved in matrix degradation (MMP-1, MMP-8, and MMP-9), xenobiotic metabolism (HO-1 and CYP1A2), and downregulation of genes involved in cell cycle regulation (including TOP2A, CCNB1, CCNA, CDKN3). Exposure of cells to a high physiological concentration of nicotine resulted in few differentially expressed genes. Immunoblot analysis of proteins selected from genes shown to be differentially regulated by microarray analysis revealed similar responses. Finally, a number of inflammatory cytokines measured in culture media were elevated in response to CSC. Together, these results describe a complex proinflammatory response, possibly mediating the recruitment of leukocytes through cytokine signaling. Additionally, fibrous cap destabilization may be facilitated by matrix metalloproteinase upregulation. PMID:14501029

  8. Electrochemical monitoring of phytochelatin accumulation in Nicotiana tabacum cells exposed to sub-cytotoxic and cytotoxic levels of cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Fojta, Miroslav [Laboratory of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno (Czech Republic)]. E-mail: fojta@ibp.cz; Fojtova, Miloslava [Laboratory of Molecular Epigenetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno (Czech Republic); Havran, Ludek [Laboratory of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno (Czech Republic); Pivonkova, Hana [Laboratory of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno (Czech Republic); Dorcak, Vlastimil [Laboratory of Biophysical Chemistry and Molecular Oncology, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, 612 65 Brno (Czech Republic); Sestakova, Ivana [J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, 182 23 Prague 8 (Czech Republic)

    2006-02-03

    Cadmium belongs to the most dangerous environmental pollutants among the toxic heavy metals seriously affecting vital functions in both animal and plant cells. It has been previously shown that cadmium ions at 50-100 {mu}M concentrations caused tobacco BY-2 (TBY-2) cells to enter apoptosis within several days of exposure. Phytochelatins (PCs), the 'plant metallothioneins', are cysteine-rich peptides involved in detoxification of heavy metals in plants. The PCs are synthesized in response to the heavy metal exposure. In this paper, we utilized electrochemical analysis to monitor accumulation of PCs in the TBY-2 cells exposed to cadmium ions. Measurements of a characteristic PC signal at mercury electrode in the presence of cobalt ions made it possible to detect changes in the cellular PC levels during the time of cultivation, starting from 30 min after exposure. Upon TBY-2 cultivation in the presence of cytotoxic cadmium concentrations, the PC levels remarkably increased during the pre-apoptotic phase and reached a limiting value at cultivation times coinciding with apoptosis trigger. The PC level observed for a sub-cytotoxic cadmium concentration (10 {mu}M) was about three-times lower than that observed for the 50 or 100 {mu}M cadmium ions after 5 days of exposure. We show that using a simple electrochemical analysis, synthesis of PCs in plant cells can be easily followed in parallel with other tests of the cellular response to the toxic heavy metal stress.

  9. PACAP and VIP inhibit the invasiveness of glioblastoma cells exposed to hypoxia through the regulation of HIFs and EGFR expression

    Directory of Open Access Journals (Sweden)

    Grazia eMaugeri

    2016-05-01

    Full Text Available Pituitary adenylate cyclase-activating polypeptide (PACAP and vasoactive intestinal peptide (VIP through the binding of vasoactive intestinal peptide receptors (VIPRs, perform a wide variety of effects in human cancers, including glioblastoma multiforme (GBM. This tumor is characterized by extensive areas of hypoxia, which triggers the expression of hypoxia-inducible factors (HIFs. HIFs not only mediate angiogenesis but also tumor cell migration and invasion. Furthermore, HIFs activation is linked to epidermal growth factor receptor (EGFR overexpression. Previous studies have shown that VIP interferes with the invasive nature of gliomas by regulating cell migration. However, the role of VIP family members in GBM infiltration under low oxygen tension has not been clarified yet. Therefore, in the present study we have investigated, for the first time, the molecular mechanisms involved in the anti-invasive effect of PACAP or VIP in U87MG glioblastoma cells exposed to hypoxia induced by treatment with desferrioxamine (DFX. The results suggest that either PACAP or VIP exert an anti-infiltrative effect under low oxygen tension by modulating HIFs and EGFR expression, key elements involved in cell migration and angiogenesis. These peptides act through the inhibition of PI3K/Akt and MAPK/ERK signaling pathways, which are known to have a crucial role in HIFs regulation. In conclusion, the modulation of hypoxic event and the anti-invasive effect exerted by some VIP family members might open new insights in the therapeutic approach to GBM.

  10. PACAP and VIP Inhibit the Invasiveness of Glioblastoma Cells Exposed to Hypoxia through the Regulation of HIFs and EGFR Expression.

    Science.gov (United States)

    Maugeri, Grazia; Grazia D'Amico, Agata; Reitano, Rita; Magro, Gaetano; Cavallaro, Sebastiano; Salomone, Salvatore; D'Agata, Velia

    2016-01-01

    Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) through the binding of vasoactive intestinal peptide receptors (VIPRs), perform a wide variety of effects in human cancers, including glioblastoma multiforme (GBM). This tumor is characterized by extensive areas of hypoxia, which triggers the expression of hypoxia-inducible factors (HIFs). HIFs not only mediate angiogenesis but also tumor cell migration and invasion. Furthermore, HIFs activation is linked to epidermal growth factor receptor (EGFR) overexpression. Previous studies have shown that VIP interferes with the invasive nature of gliomas by regulatin